The syntaxin Tlg1p mediates trafficking of chitin synthase III to polarized growth sites in yeast

Tlg1p and Tlg2p, members of the syntaxin family of SNAREs in yeast, have been implicated in both endocytosis and the retention of late Golgi markers. We have investigated the functions of these and the other endocytic syntaxins Pep12p and Vam3p. Remarkably, growth is possible in the absence of all f...

Full description

Saved in:
Bibliographic Details
Published in:Molecular biology of the cell 1998-12, Vol.9 (12), p.3383-3397
Main Authors: Holthuis, J C, Nichols, B J, Pelham, H R
Format: Article
Language:English
Subjects:
Biological Transport, Active
Cell Polarity
Chitin Synthase - metabolism
Endocytosis
Endosomes - metabolism
Exocytosis
Fungal Proteins - metabolism
Golgi Apparatus - metabolism
Membrane Fusion
Membrane Proteins - metabolism
Microscopy, Electron
Qa-SNARE Proteins
Saccharomyces cerevisiae - cytology
Saccharomyces cerevisiae - growth & development
Saccharomyces cerevisiae - metabolism
SNARE Proteins
Vesicular Transport Proteins
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Tlg1p and Tlg2p, members of the syntaxin family of SNAREs in yeast, have been implicated in both endocytosis and the retention of late Golgi markers. We have investigated the functions of these and the other endocytic syntaxins Pep12p and Vam3p. Remarkably, growth is possible in the absence of all four proteins. In the absence of the others, Pep12p and Tlg1p can each create endosomes accessible to the endocytic tracer dye FM4-64. However, although Pep12p is required for the ligand-induced internalization of the alpha factor receptor and its passage via Pep12p-containing membranes to the vacuole, Tlg1p is not. In contrast, Tlg1p is required for the efficient localization of the catalytic subunit of chitin synthase III (Chs3p) to the bud neck, a process that involves endocytosis and polarized delivery of Chs3p. In wild-type cells, internalized Chs3p cofractionates with Tlg1p and Tlg2p, and in a strain lacking the other endocytic syntaxins, either Tlg1p or Tlg2p is sufficient for correct localization of the enzyme. Pep12p is neither necessary nor sufficient for this process. We conclude that there are two endocytic routes in yeast that can operate independently and that Tlg1p is located at the junction of one of these with the polarized exocytic pathway.
ISSN:1059-1524
1939-4586
DOI:10.1091/mbc.9.12.3383