A selective transport route from golgi to late endosomes that requires theyeast GGA proteins

Citation
Mw. Black et Hrb. Pelham, A selective transport route from golgi to late endosomes that requires theyeast GGA proteins, J CELL BIOL, 151(3), 2000, pp. 587-600
Citations number
45
Categorie Soggetti
Cell & Developmental Biology
Journal title
JOURNAL OF CELL BIOLOGY
ISSN journal
00219525 → ACNP
Volume
151
Issue
3
Year of publication
2000
Pages
587 - 600
Database
ISI
SICI code
0021-9525(20001030)151:3<587:ASTRFG>2.0.ZU;2-B
Abstract
Pep12p is a yeast syntaxin located primarily in late endosomes. Using mutag enesis of a green fluorescent protein chimera we have identified a sorting signal FSDSPEF, which is required for transport of Pep12p from the exocytic pathway to late endosomes, from which it can, when overexpressed, reach th e vacuole. When this signal is mutated, Pep12p instead passes to early endo somes, a step that is determined by its transmembrane domain. Surprisingly, Pep12p is then specifically retained in early endosomes and does not go on to late endosomes. By testing appropriate chimeras in mutant strains, we found that FSDSPEF-de pendent sorting was abolished in strains lacking Gga1p and Gga2p, Golgi-ass ociated coat proteins with homology to gamma adaptin, In the gga1 gga2 doub le mutant endogenous Pep12p cofractionated with the early endosome marker T lg1p, and recycling of Snc1p through early endosomes was defective. Pep12p sorting was also defective in cells lacking the clathrin heavy or light cha in. We suggest that specific and direct delivery of proteins to early and l ate endosomes is required to maintain the functional heterogeneity of the e ndocytic pathway and that the GGA proteins, probably in association with cl athrin, help create vesicles destined for late endosomes.