tailieunhanh - Báo cáo khoa học: Plant RMR proteins: unique vacuolar sorting receptors that couple ligand sorting with membrane internalization

In receptor-mediated sorting of soluble protein ligands in the endomem-brane system of eukaryotic cells, three completely different receptor pro-teins for mammalian (mannose 6-phosphate receptor), yeast (Vps10p) and plant cells (vacuolar sorting receptor; VSR) have in common the features of pH-dependent ligand binding and receptor recycling. | IFEBS Journal MINIREVIEW Plant RMR proteins unique vacuolar sorting receptors that couple ligand sorting with membrane internalization Hao Wang1 2 John C. Rogers3 and Liwen Jiang1 2 1 Department of Biology Centre for Celland DevelopmentalBiology Chinese University of Hong Kong China 2 State China Key Laboratory for Agrobaiotechnology The Chinese University of Hong Kong China 3 Institute of BiologicalChemistry Washington State University Pullman WA USA Keywords lytic PVC PA domain pollen tube PSV receptor RING-H2 domain RMR storage PVC vacuole VSR Correspondence L. Jiang State China Key Laboratory for Agrobaiotechnology The Chinese University of Hong Kong Shatin New Territories Hong Kong China Fax 852 2603 5646 Tel 852 2609 6388 E-mail ljiang@ Received 31 March 2010 revised 30 June 2010 accepted 7 July 2010 In receptor-mediated sorting of soluble protein ligands in the endomembrane system of eukaryotic cells three completely different receptor proteins for mammalian mannose 6-phosphate receptor yeast Vps10p and plant cells vacuolar sorting receptor VSR have in common the features of pH-dependent ligand binding and receptor recycling. In striking contrast the plant receptor homology-transmembrane-RING-H2 RMR proteins serve as sorting receptors to a separate type of vacuole the protein storage vacuole but do not recycle and their trafficking pathway results in their internalization into the destination vacuole. Even though plant RMR proteins share high sequence similarity with the best-characterized mammalian PA-TM-RING family proteins these two families of proteins appear to play distinctly different roles in plant and animal cells. Thus this minireview focuses on this unique sorting mechanism and traffic of RMR proteins via dense vesicles in various plant cell types. doi Introduction Eukaryotic cells share a common organization of organelles within their endomembrane systems where each is a membrane-bound compartment which