MyMedR

Displaying publications 41 - 60 of 199 in total

Abstract:

Sort:

Beta-sheet containment by flanking prolines: molecular dynamic simulations of the inhibition of beta-sheet elongation by proline residues in human prion protein

Shamsir MS, Dalby AR

Biophys J, 2007 Mar 15;92(6):2080-9.
PMID: 17172295

Previous molecular dynamic simulations have reported elongation of the existing beta-sheet in prion proteins. Detailed examination has shown that these elongations do not extend beyond the proline residues flanking these beta-sheets. In addition, proline has also been suggested to possess a possible structural role in preserving protein interaction sites by preventing invasion of neighboring secondary structures. In this work, we have studied the possible structural role of the flanking proline residues by simulating mutant structures with alternate substitution of the proline residues with valine. Simulations showed a directional inhibition of elongation, with the elongation progressing in the direction of valine including evident inhibition of elongation by existing proline residues. This suggests that the flanking proline residues in prion proteins may have a containment role and would confine the beta-sheet within a specific length.

Matched MeSH terms: Membrane Proteins/ultrastructure*; Membrane Proteins/chemistry*
Fulltext Membrane-bound Gaussia luciferase as a tool to track shedding of membrane proteins from the surface of extracellular vesicles

Zaborowski MP, Cheah PS, Zhang X, Bushko I, Lee K, Sammarco A, et al.

Sci Rep, 2019 Nov 22;9(1):17387.
PMID: 31758005 DOI: 10.1038/s41598-019-53554-y

Extracellular vesicles (EVs) released by cells play a role in intercellular communication. Reporter and targeting proteins can be modified and exposed on the surface of EVs to investigate their half-life and biodistribution. A characterization of membrane-bound Gaussia luciferase (mbGluc) revealed that its signal was detected also in a form smaller than common EVs (<70 nm). We demonstrated that mbGluc initially exposed on the surface of EVs, likely undergoes proteolytic cleavage and processed fragments of the protein are released into the extracellular space in active form. Based on this observation, we developed a new assay to quantitatively track shedding of membrane proteins from the surface of EVs. We used this assay to show that ectodomain shedding in EVs is continuous and is mediated by specific proteases, e.g. metalloproteinases. Here, we present a novel tool to study membrane protein cleavage and release using both in vitro and in vivo models.

Matched MeSH terms: Membrane Proteins/genetics; Membrane Proteins/metabolism*
Fulltext Crystal structure of an antigenic outer-membrane protein from Salmonella Typhi suggests a potential antigenic loop and an efflux mechanism

Guan HH, Yoshimura M, Chuankhayan P, Lin CC, Chen NC, Yang MC, et al.

Sci Rep, 2015 Nov 13;5:16441.
PMID: 26563565 DOI: 10.1038/srep16441

ST50, an outer-membrane component of the multi-drug efflux system from Salmonella enterica serovar Typhi, is an obligatory diagnostic antigen for typhoid fever. ST50 is an excellent and unique diagnostic antigen with 95% specificity and 90% sensitivity and is used in the commercial diagnosis test kit (TYPHIDOT(TM)). The crystal structure of ST50 at a resolution of 2.98 Å reveals a trimer that forms an α-helical tunnel and a β-barrel transmembrane channel traversing the periplasmic space and outer membrane. Structural investigations suggest significant conformational variations in the extracellular loop regions, especially extracellular loop 2. This is the location of the most plausible antibody-binding domain that could be used to target the design of new antigenic epitopes for the development of better diagnostics or drugs for the treatment of typhoid fever. A molecule of the detergent n-octyl-β-D-glucoside is observed in the D-cage, which comprises three sets of Asp361 and Asp371 residues at the periplasmic entrance. These structural insights suggest a possible substrate transport mechanism in which the substrate first binds at the periplasmic entrance of ST50 and subsequently, via iris-like structural movements to open the periplasmic end, penetrates the periplasmic domain for efflux pumping of molecules, including poisonous metabolites or xenobiotics, for excretion outside the pathogen.

Matched MeSH terms: Bacterial Outer Membrane Proteins/genetics; Bacterial Outer Membrane Proteins/metabolism; Bacterial Outer Membrane Proteins/chemistry*
Fulltext Genetic diversity and natural selection in the rhoptry-associated protein 1 (RAP-1) of recent Plasmodium knowlesi clinical isolates from Malaysia

Rawa MS, Fong MY, Lau YL

Malar J, 2016;15:62.
PMID: 26847346 DOI: 10.1186/s12936-016-1127-7

The Plasmodium rhoptry-associated protein 1 (RAP-1) plays a role in the formation of the parasitophorous vacuole following the parasite's invasion of red blood cells. Although there is some evidence that the protein is recognized by the host's immune system, study of Plasmodium falciparum RAP-1 (PfRAP-1) suggests that it is not under immune pressure. A previous study on five old (1953-1962) P. knowlesi strains suggested that RAP-1 has limited genetic polymorphism and might be under negative selection. In the present study, 30 recent P. knowlesi isolates were studied to obtain a better insight into the polymorphism and natural selection of PkRAP-1.

Matched MeSH terms: Membrane Proteins
Structural and functional studies of a 50 kDa antigenic protein from Salmonella enterica serovar Typhi

Choong YS, Lim TS, Chew AL, Aziah I, Ismail A

J Mol Graph Model, 2011 Apr;29(6):834-42.
PMID: 21371926 DOI: 10.1016/j.jmgm.2011.01.008

The high typhoid incidence rate in developing and under-developed countries emphasizes the need for a rapid, affordable and accessible diagnostic test for effective therapy and disease management. TYPHIDOT®, a rapid dot enzyme immunoassay test for typhoid, was developed from the discovery of a ∼50 kDa protein specific for Salmonella enterica serovar Typhi. However, the structure of this antigen remains unknown till today. Studies on the structure of this antigen are important to elucidate its function, which will in turn increase the efficiency of the development and improvement of the typhoid detection test. This paper described the predictive structure and function of the antigenically specific protein. The homology modeling approach was employed to construct the three-dimensional structure of the antigen. The built structure possesses the features of TolC-like outer membrane protein. Molecular docking simulation was also performed to further probe the functionality of the antigen. Docking results showed that hexamminecobalt, Co(NH(3))(6)(3+), as an inhibitor of TolC protein, formed favorable hydrogen bonds with D368 and D371 of the antigen. The single point (D368A, D371A) and double point (D368A and D371A) mutations of the antigen showed a decrease (single point mutation) and loss (double point mutations) of binding affinity towards hexamminecobalt. The architecture features of the built model and the docking simulation reinforced and supported that this antigen is indeed the variant of outer membrane protein, TolC. As channel proteins are important for the virulence and survival of bacteria, therefore this ∼50 kDa channel protein is a good specific target for typhoid detection test.

Matched MeSH terms: Membrane Proteins/genetics; Membrane Proteins/metabolism; Membrane Proteins/chemistry
Fulltext Cytosolic DNA sensing through cGAS and STING is inactivated by gene mutations in pangolins

Fischer H, Tschachler E, Eckhart L

Apoptosis, 2020 08;25(7-8):474-480.
PMID: 32533513 DOI: 10.1007/s10495-020-01614-4

The release of DNA into the cytoplasm upon damage to the nucleus or during viral infection triggers an interferon-mediated defense response, inflammation and cell death. In human cells cytoplasmic DNA is sensed by cyclic GMP-AMP Synthase (cGAS) and Absent In Melanoma 2 (AIM2). Here, we report the identification of a "natural knockout" model of cGAS. Comparative genomics of phylogenetically diverse mammalian species showed that cGAS and its interaction partner Stimulator of Interferon Genes (STING) have been inactivated by mutations in the Malayan pangolin whereas other mammals retained intact copies of these genes. The coding sequences of CGAS and STING1 are also disrupted by premature stop codons and frame-shift mutations in Chinese and tree pangolins, suggesting that expression of these genes was lost in a common ancestor of all pangolins that lived more than 20 million years ago. AIM2 is retained in a functional form in pangolins whereas it is inactivated by mutations in carnivorans, the phylogenetic sister group of pangolins. The deficiency of cGAS and STING points to the existence of alternative mechanisms of controlling cytoplasmic DNA-associated cell damage and viral infections in pangolins.

Matched MeSH terms: Membrane Proteins/deficiency; Membrane Proteins/genetics*; Membrane Proteins/immunology
Fulltext Entamoeba histolytica: Proteomics Bioinformatics Reveal Predictive Functions and Protein-Protein Interactions of Differentially Abundant Membrane and Cytosolic Proteins

Azmi N, Othman N

Membranes (Basel), 2021 May 21;11(6).
PMID: 34063994 DOI: 10.3390/membranes11060376

Amoebiasis is caused by Entamoeba histolytica and ranked second for parasitic diseases causing death after malaria. E. histolytica membrane and cytosolic proteins play important roles in the pathogenesis. Our previous study had shown several cytosolic proteins were found in the membrane fraction. Therefore, this study aimed to quantify the differential abundance of membrane and cytosolic proteins in membrane versus cytosolic fractions and analyze their predicted functions and interaction. Previous LC-ESI-MS/MS data were analyzed by PERSEUS software for the differentially abundant proteins, then they were classified into their functional annotations and the protein networks were summarized using PantherDB and STRiNG, respectively. The results showed 24 (44.4%) out of the 54 proteins that increased in abundance were membrane proteins and 30 were cytosolic proteins. Meanwhile, 45 cytosolic proteins were found to decrease in abundance. Functional analysis showed differential abundance proteins involved in the molecular function, biological process, and cellular component with 18.88%, 33.04% and, 48.07%, respectively. The STRiNG server predicted that the decreased abundance proteins had more protein-protein network interactions compared to increased abundance proteins. Overall, this study has confirmed the presence of the differentially abundant membrane and cytosolic proteins and provided the predictive functions and interactions between them.

Matched MeSH terms: Membrane Proteins
Improved DNA delivery using invasive E. coli DH10B in human cells by modified bactofection method

Sultana A, Tiash S

J Control Release, 2021 04 10;332:233-244.
PMID: 33561481 DOI: 10.1016/j.jconrel.2021.02.004

E. coli mediated gene delivery faces a major drawback of low efficiency despite of being a safer alternative to viral vectors. This study showed a novel, simple and effective strategy to enhance invasive E. coli DH10B vector's efficiency in human epithelial cells. The bactofection efficiency of invasive E .coli vector was analyzed in nine cell lines. It demonstrated highest (16%) reporter gene (GFP) expression in cervical cells. Methods were employed to further enhance its efficiency by adding transfection reagents (trans-bactofection method) to promote entry into host cells, lysosomotropic reagents for escape from lysosomal degradation or antibiotics to lyse internalized bacteria. Increased bacterial entry, as elucidated from nil to 3% expression in liver cells, was obtained upon complexing bacteria with PULSin. Chloroquine mediated endosomal escape resulted in 7.2 folds increase whereas tetracycline addition to lyse internalized bacteria caused ≈90% of GFP in HeLa. Eventually, the combined effect of these three methods exhibited close to 100% GFP in cervical and remarkable increase of 138 folds in breast cells. This is the first study showing comparative study of vector's gene delivery ability in various epithelial cells of the human body with improving its delivery efficiency. These data demonstrated the potential of developed bactofection method to boost up the efficiency of other bacterial vectors also, which could further be used for effectual therapeutic gene delivery in human cells.

Matched MeSH terms: Bacterial Outer Membrane Proteins
Fulltext TAL - a source of bacterial endotoxin detector in liquid biological samples

Akbar John, B., Kamaruzzaman, B.Y., Jalal, K.C.A., Zaleha, K.

International Food Research Journal, 2012;19(2):423-425.
MyJurnal

Endotoxins (chemically known as Lipopolysaccharide) from gram-negative microorganisms initiates clot formation in blood when it is accidentally encountered by horseshoe crab blood stream. This property was extensively studied by various researchers as a result Limulus Amebocyte Lysate (LAL) test was established. The LAL tests in general, 3 to 300 times more sensitive than the United States Pharmacopeial (USP) rabbit pyrogen test method. It is apparent that major differences among the LAL preparations lie in the area of sensitivity. Differences, up to 100-fold, exist in the sensitivity of the various LAL preparations to the same endotoxin. Based on the above perspective, a portable Kit (Endo sensor) was developed to detect the presence of bacterial endotoxin in liquid biological samples using Tachypleus Amebocyte Lysate (TAL) as a source. Sensitivity of the Kit was determined using various concentrations of prepared endotoxin standards and pyrogen free water samples. It was observed that Endo sensor could detect up to nano gram level of endotoxin in liquid biological samples which could be expressed in (EU/ml) and the labeled sensitivity of the lysated product was 0.125 EU/ml. The gel clotting principle method was utilized for the detection of bacterial endotoxin in liquid biological samples.

Matched MeSH terms: Membrane Proteins
Fulltext Clinical and histopathological relevance of helicobacter pylori BabA2 genotype

Tariq Elhashim, M. Imad Mustafa Mahmud, Nasser Amjad, Norra Harun, Imad M. Alani

International Medical Journal Malaysia, 2016;15(2):43-49.
MyJurnal

Introduction: H. pylori BabA is an outer membrane protein that mediates bacterial adherence to the gastric
epithelium, triggers several pathways during the course of infection, and thus contributes to the disease
development. Considering the variability in the presence of BabA coding gene (babA2) among H. pylori
clinical strains, the aim of this study was to assess the relationship between the genotype status of H. pylori
babA2 and the severity of clinical and histopathological outcomes. Methods: Gastric mucosal biopsy
specimens were collected from 30 CLO test-positive patients, 16 with gastritis and 14 with peptic ulcer
disease. Polymerase chain reaction was carried out to detect the presence of H. pylori-specific glmM gene
and BabA coding gene (babA2). Histopathological examination was performed to evaluate the severity of H.
pylori-associated gastric disease according to the Updated Sydney Classification System. Results: The glmM
and babA2 genes were present in 100% and 86.7% of the tested H. pylori strains, respectively. Although
higher degrees of inflammatory activity and H. pylori density were noted in babA2-positive biopsy
specimens, there was no statistically significant association between babA2 genotype status and the severity
of gastric disease. Conclusion: The babA2 genotype status of H. pylori may not be considered as a sole
marker for determining the infection outcomes.

Matched MeSH terms: Membrane Proteins
Analysis of reactive astrocytes and NG2 proteoglycan in ex vivo rat models of spinal cord injury

Patar A, Dockery P, Howard L, McMahon S

J Neurosci Methods, 2019 01 01;311:418-425.
PMID: 30267723 DOI: 10.1016/j.jneumeth.2018.09.027

BACKGROUND: The use of animals to model spinal cord injury (SCI) requires extensive post-operative care and can be expensive, which makes an alternative model extremely attractive. The use ofex vivo slice cultures is an alternative way to study the pathophysiological changes that can mimic in vivo conditions and support the 3Rs (replacement, reduction and refinement) of animal use in SCI research models.
NEW METHOD: In this study the presence of reactive astrocytes and NG2 proteoglycans was investigated in two ex vivo models of SCI; stab injury and transection injury. Stereological analysis to measure immunohistochemical staining was performed on the scar and injury zones to detect astrocytes and the chondroitin sulphate proteoglycan NG2.
RESULTS: The volume fraction (Vv) of reactive astrocytes and NG2 proteoglycans increased significantly between day 3 and day 10 post injury in both ex vivo models. This data shows how ex vivo SCI models are a useful research tool allowing reduction of research cost and time involved in carrying out animal studies, as well as reducing the numbers of animals used.
COMPARISON WITH EXISTING METHOD: This is the first evidence of an ex vivo stab injury model of SCI and also the first comparison of immunohistochemical staining for injury markers within stab injured and transection injured ex vivo slice cultures.
CONCLUSIONS: The use of organotypic slice culture models provide a simple way to study the cellular consequences following SCI and they can also be used as a platform for potential therapeutics regimes for the treatment of SCI.

Matched MeSH terms: Membrane Proteins
Proteomics as a tool for tapping potential of entomopathogens as microbial insecticides

Harith Fadzilah N, Abdul-Ghani I, Hassan M

Arch Insect Biochem Physiol, 2019 Jan;100(1):e21520.
PMID: 30426561 DOI: 10.1002/arch.21520

Biopesticides are collective pest control harnessing the knowledge of the target pest and its natural enemies that minimize the risks of synthetic pesticides. A subset of biopesticides; bioinsecticides, are specifically used in controlling insect pests. Entomopathogens (EPMs) are micro-organisms sought after as subject for bioinsecticide development. However, lack of understanding of EPM mechanism of toxicity and pathogenicity slowed the progress of bioinsecticide development. Proteomics is a useful tool in elucidating the interaction of entomopathogenic fungi, entomopathogenic bacteria, and entomopathogenic virus with their target host. Collectively, proteomics shed light onto insect host response to EPM infection, mechanism of action of EPM's toxic proteins and secondary metabolites besides characterizing secreted and membrane-bound proteins of EPM that more precisely describe relevant proteins for host recognition and mediating pathogenesis. However, proteomics requires optimized protein extraction methods to maximize the number of proteins for analysis and availability of organism's genome for a more precise protein identification.

Matched MeSH terms: Membrane Proteins
Analysis of core protein clusters identifies candidate variable sites conferring metronidazole resistance in Helicobacter pylori

Chua EG, Debowski AW, Webberley KM, Peters F, Lamichhane B, Loke MF, et al.

Gastroenterol Rep (Oxf), 2019 Feb;7(1):42-49.
PMID: 30792865 DOI: 10.1093/gastro/goy048

Background: Metronidazole is one of the first-line drugs of choice in the standard triple therapy used to eradicate Helicobacter pylori infection. Hence, the global emergence of metronidazole resistance in Hp poses a major challenge to health professionals. Inactivation of RdxA is known to be a major mechanism of conferring metronidazole resistance in H. pylori. However, metronidazole resistance can also arise in H. pylori strains expressing functional RdxA protein, suggesting that there are other mechanisms that may confer resistance to this drug.
Methods: We performed whole-genome sequencing on 121 H. pylori clinical strains, among which 73 were metronidazole-resistant. Sequence-alignment analysis of core protein clusters derived from clinical strains containing full-length RdxA was performed. Variable sites in each alignment were statistically compared between the resistant and susceptible groups to determine candidate genes along with their respective amino-acid changes that may account for the development of metronidazole resistance in H. pylori.
Results: Resistance due to RdxA truncation was identified in 34% of metronidazole-resistant strains. Analysis of core protein clusters derived from the remaining 48 metronidazole-resistant strains and 48 metronidazole-susceptible identified four variable sites significantly associated with metronidazole resistance. These sites included R16H/C in RdxA, D85N in the inner-membrane protein RclC (HP0565), V265I in a biotin carboxylase protein (HP0370) and A51V/T in a putative threonylcarbamoyl-AMP synthase (HP0918).
Conclusions: Our approach identified new potential mechanisms for metronidazole resistance in H. pylori that merit further investigation.

Matched MeSH terms: Membrane Proteins
Gene expression profiling of host lipid metabolism in SARS-CoV-2 infected patients: a systematic review and integrated bioinformatics analysis

Munawar WASWA, Elias MH, Addnan FH, Hassandarvish P, AbuBakar S, Roslan N

BMC Infect Dis, 2024 Jan 23;24(1):124.
PMID: 38263024 DOI: 10.1186/s12879-024-08983-0

BACKGROUND: The Coronavirus disease 2019 (COVID-19) pandemic occurred due to the dispersion of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Severe symptoms can be observed in COVID-19 patients with lipid-related comorbidities such as obesity and diabetes. Yet, the extensive molecular mechanisms of how SARS-CoV-2 causes dysregulation of lipid metabolism remain unknown.
METHODS: Here, an advanced search of articles was conducted using PubMed, Scopus, EBSCOhost, and Web of Science databases using terms from Medical Subject Heading (MeSH) like SARS-CoV-2, lipid metabolism and transcriptomic as the keywords. From 428 retrieved studies, only clinical studies using next-generation sequencing as a gene expression method in COVID-19 patients were accepted. Study design, study population, sample type, the method for gene expression and differentially expressed genes (DEGs) were extracted from the five included studies. The DEGs obtained from the studies were pooled and analyzed using the bioinformatics software package, DAVID, to determine the enriched pathways. The DEGs involved in lipid metabolic pathways were selected and further analyzed using STRING and Cytoscape through visualization by protein-protein interaction (PPI) network complex.
RESULTS: The analysis identified nine remarkable clusters from the PPI complex, where cluster 1 showed the highest molecular interaction score. Three potential candidate genes (PPARG, IFITM3 and APOBEC3G) were pointed out from the integrated bioinformatics analysis in this systematic review and were chosen due to their significant role in regulating lipid metabolism. These candidate genes were significantly involved in enriched lipid metabolic pathways, mainly in regulating lipid homeostasis affecting the pathogenicity of SARS-CoV-2, specifically in mechanisms of viral entry and viral replication in COVID-19 patients.
CONCLUSIONS: Taken together, our findings in this systematic review highlight the affected lipid-metabolic pathways along with the affected genes upon SARS-CoV-2 invasion, which could be a potential target for new therapeutic strategies study in the future.

Matched MeSH terms: Membrane Proteins
Fulltext Expression of full-length Plasmodium falciparum P48/45 in P. berghei blood stages: A method to express and evaluate vaccine antigens

Othman AS, Lin JW, Franke-Fayard BM, Kroeze H, van Pul FJA, Chevalley-Maurel S, et al.

Mol Biochem Parasitol, 2018 Sep;224:44-49.
PMID: 30053393 DOI: 10.1016/j.molbiopara.2018.07.009

The transmission-blocking vaccine candidate Pfs48/45 from the human malaria parasite Plasmodium falciparum is known to be difficult to express in heterologous systems, either as full-length protein or as correctly folded protein fragments that retain conformational epitopes. In this study we express full-length Pfs48/45 in the rodent parasite P. berghei. Pfs48/45 is expressed as a transgene under control of the strong P. berghei schizont-specific msp1 gene promoter (Pfs48/45@PbMSP1). Pfs48/45@PbMSP1 schizont-infected red blood cells produced full-length Pfs48/45 and the structural integrity of Pfs48/45 was confirmed using a panel of conformation-specific monoclonal antibodies that bind to different Pfs48/45 epitopes. Sera from mice immunized with transgenic Pfs48/45@PbMSP1 schizonts showed strong transmission-reducing activity in mosquitoes infected with P. falciparum using standard membrane feeding. These results demonstrate that transgenic rodent malaria parasites expressing human malaria antigens may be used as means to evaluate immunogenicity and functionality of difficult to express malaria vaccine candidate antigens.

Matched MeSH terms: Membrane Proteins/biosynthesis; Membrane Proteins/genetics; Membrane Proteins/immunology*
Fulltext Remote Monitoring of COVID-19 Patients Using Multisensor Body Area Network Innovative System

Al-Barazanchi I, Hashim W, Ahmed Alkahtani A, Rasheed Abdulshaheed H, Muwafaq Gheni H, Murthy A, et al.

Comput Intell Neurosci, 2022;2022:9879259.
PMID: 36156952 DOI: 10.1155/2022/9879259

As of late 2019, the COVID19 pandemic has been causing huge concern around the world. Such a pandemic posed serious threats to public safety, the well-being of healthcare workers, and the overall health of the population. If automation can be implemented in healthcare systems, patients could be better cared for and health industries could be less burdened. To combat such challenges, e-health requires apps and intelligent systems. Using WBAN sensors and networks, a doctor or medical professional can advise patients on the best course of action. Patients' fitness could be assessed using WBAN sensors without interfering with their daily activities. When designing a monitoring system, system performance reliability for competent healthcare is critical. Existing research has failed to create a large device capable of handling a large network or to improve WBAN topologies for fast transmitting and receiving patient data. As a result, in this research, we create a multisensor WBAN (MSWBAN) intelligent system for transmitting and receiving critical patient data. To gather information from all cluster nodes and send it to multisensor WBAN, a novel additive distance-threshold routing protocol (ADTRP) is proposed. In small networks where data are managed by the transmitting node and the best data route is determined, this protocol has less redundancy. An edge-cutting-based routing optimization (ES-EC-R ES-EC-RO) is used to find the best route. The Trouped blowfish MD5 (TB-MD5) algorithm is used to encrypt and decrypt data, and the encrypted data are stored in a cloud database for security. The performance metrics of our proposed model are compared to current techniques for the best results. End-to-end latency is 63 ms, packet delivery is 95%, security is 95.7%, and throughput is 9120 bps, according to the results. The purpose of this article is to encourage engineers and front-line workers to develop digital health systems for tracking and controlling virus outbreaks.

Matched MeSH terms: Membrane Proteins
The kinase LMTK3 promotes invasion in breast cancer through GRB2-mediated induction of integrin β₁

Xu Y, Zhang H, Lit LC, Grothey A, Athanasiadou M, Kiritsi M, et al.

Sci Signal, 2014 Jun 17;7(330):ra58.
PMID: 24939894 DOI: 10.1126/scisignal.2005170

Lemur tyrosine kinase 3 (LMTK3) is associated with cell proliferation and endocrine resistance in breast cancer. We found that, in cultured breast cancer cell lines, LMTK3 promotes the development of a metastatic phenotype by inducing the expression of genes encoding integrin subunits. Invasive behavior in various breast cancer cell lines positively correlated with the abundance of LMTK3. Overexpression of LMTK3 in a breast cancer cell line with low endogenous LMTK3 abundance promoted actin cytoskeleton remodeling, focal adhesion formation, and adhesion to collagen and fibronectin in culture. Using SILAC (stable isotope labeling by amino acids in cell culture) proteomic analysis, we found that LMTK3 increased the abundance of integrin subunits α5 and β1, encoded by ITGA5 and ITGB1. This effect depended on the CDC42 Rho family guanosine triphosphatase, which was in turn activated by the interaction between LMTK3 and growth factor receptor-bound protein 2 (GRB2), an adaptor protein that mediates receptor tyrosine kinase-induced activation of RAS and downstream signaling. Knockdown of GRB2 suppressed LMTK3-induced CDC42 activation, blocked ITGA5 and ITGB1 expression promoted by the transcription factor serum response factor (SRF), and reduced invasive activity. Furthermore, abundance of LMTK3 positively correlated with that of the integrin β1 subunit in breast cancer patient's tumors. Our findings suggest a role for LMTK3 in promoting integrin activity during breast cancer progression and metastasis.

Matched MeSH terms: Membrane Proteins/metabolism*
Fulltext Molecular markers of dental pulp tissue during orthodontic tooth movement: a pilot study

Abdul Wahab RM, Zainal Ariffin SH, Yeen WW, Ahmad NA, Senafi S

ScientificWorldJournal, 2012;2012:236427.
PMID: 22629122 DOI: 10.1100/2012/236427

Three specific orthodontic tooth movement genes, that is, FCRL1, HSPG2, and LAMB2 were detected at upper first premolar (with appliance) dental pulp tissue by using GeneFishing technique as compared to lower first premolar (without appliance). These three differentially expressed genes have the potential as molecular markers during orthodontic tooth movement by looking at molecular changes of pulp tissue.

Matched MeSH terms: Membrane Proteins/metabolism*
A 35 kDa antigenic protein from Shigella flexneri: in silico structural and functional studies

Yung-Hung RL, Ismail A, Lim TS, Choong YS

Biochem Biophys Res Commun, 2011 Nov 18;415(2):229-34.
PMID: 21982766 DOI: 10.1016/j.bbrc.2011.09.116

Shigella flexneri serotype 2a is a major public health concern in the developing and under-developed countries which contributes to shigellosis endemic and mortality. Thus, there is an urgent need for a rapid diagnostic test for effective therapy and disease management. Previous study showed that a ∼35 kDa antigenic protein from S. flexneri is a potential biomarker. We therefore modelled the three-dimensional structure of the antigen to probe its functionality which could aid in the development of an antigen-based diagnostic. Results showed that the antigen is a transmembrane protein consists of OmpA and OmpA-like domains. The OmpA domain is a beta-barrel embedded in the outer membrane with four surface-exposed extracellular loops. The OmpA-like domain is linked to the OmpA domain with a 17 amino acids linker and located in the periplasmic. Docking of peptidoglycan into the groove of OmpA-like domain might help in catalyzing the bacterial cell wall formation. Both domains are expected to be involved in the virulence, structural stability, pathogenesis and survival of Shigella thus made the 35 kDa protein a suitable shigellosis diagnostic biomarker. This structural elucidation will also enable a better identification of the epitope regions for the development of specific binders to the 35 kDa antigen.

Matched MeSH terms: Bacterial Outer Membrane Proteins/chemistry*
Fulltext p63 as a complimentary basal cell specific marker to high molecular weight-cytokeratin in distinguishing prostatic carcinoma from benign prostatic lesions

Shiran MS, Tan GC, Sabariah AR, Rampal L, Phang KS

Med J Malaysia, 2007 Mar;62(1):36-9.
PMID: 17682568 MyJurnal

The diagnosis of prostatic carcinoma (Pca) on routine biopsies may be challenging, and to date the commonly used marker to distinguish prostate carcinoma from benign prostatic lesions has been High Molecular Weight-Cytokeratin (HMW-CK). However, the antigen of HMW-CK is susceptible to the effect of formalin fixation and causes frequent loss or patchy staining in the obviously benign glands. More recently, antibodies to p63 have been reported to be more sensitive than HMW-CK for the detection of prostatic basal cells. p63, a homologue of tumour suppressor gene p53, is essential for prostate development and is selectively expressed in the nuclei of basal cells of normal prostate glands. The objective of this study is to compare the sensitivity and specificity of HMW-CK and p63 in distinguishing prostatic carcinomas from benign prostatic lesions, as well as determining their positive predictive values. Seventy-two cases from HUKM (comprising 29 prostatic carcinomas and 43 benign prostatic hyperplasias) were stained for both HMW-CK and p63. The sensitivity of p63 and HMW-CK in identifying basal cells in benign glands was 88.37% and 90.70% respectively. The specificity of both reagents was 100%, and the positive predictive value for both reagents was also 100%. Thus, p63 is a useful complementary basal cell specific stain to HMW-CK, and would be very helpful to practicing pathologists in dealing with difficult cases.

Matched MeSH terms: Membrane Proteins*

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links