Affiliations 

  • 1 School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
  • 2 Tun Abdul Razak Research Centre, Brickendonbury, Hertford SG13 8NL, UK
  • 3 Malaysian Rubber Board, Experiment Station, 47000 Sungai Buloh, Selangor DE, Malaysia
J. Exp. Bot., 2017 Nov 02;68(18):5045-5055.
PMID: 29036360 DOI: 10.1093/jxb/erx331

Abstract

Natural rubber (polyisoprene) from the rubber tree Hevea brasiliensis is synthesized by specialized cells called laticifers. It is not clear how rubber particles arise, although one hypothesis is that they derive from the endoplasmic reticulum (ER) membrane. Here we cloned the genes encoding four key proteins found in association with rubber particles and studied their intracellular localization by transient expression in Nicotiana benthamiana leaves. We show that, while the cis-prenyltransferase (CPT), responsible for the synthesis of long polyisoprene chains, is a soluble, cytosolic protein, other rubber particle proteins such as rubber elongation factor (REF), small rubber particle protein (SRPP) and Hevea rubber transferase 1-REF bridging protein (HRBP) are associated with the endoplasmic reticulum (ER). We also show that SRPP can recruit CPT to the ER and that interaction of CPT with HRBP leads to both proteins relocating to the plasma membrane. We discuss these results in the context of the biogenesis of rubber particles.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.