A yeast t-SNARE involved in endocytosis

• Published in: Molecular biology of the cell 1998-10, Vol.9 (10), p.2873-2889
• Main Authors: Séron, K, Tieaho, V, Prescianotto-Baschong, C, Aust, T, Blondel, M O, Guillaud, P, Devilliers, G, Rossanese, O W, Glick, B S, Riezman, H, Keränen, S, Haguenauer-Tsapis, R
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Chromosomes, Fungal; Cloning, Molecular; Endocytosis - physiology; Fungal Proteins - biosynthesis; Fungal Proteins - genetics; Gene Deletion; Guanine Nucleotide Exchange Factors; Kinetics; Mating Factor; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane Transport Proteins - genetics; Membrane Transport Proteins - metabolism; Molecular Sequence Data; Nucleotide Transport Proteins; Open Reading Frames; Organelles - physiology; Organelles - ultrastructure; Peptides - genetics; Peptides - metabolism; Proton-Translocating ATPases - genetics; Proton-Translocating ATPases - metabolism; Qa-SNARE Proteins; Recombinant Fusion Proteins - biosynthesis; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - physiology; Saccharomyces cerevisiae Proteins; Sequence Alignment; Sequence Homology, Amino Acid; Vacuolar Proton-Translocating ATPases
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.9.10.2873

The ORF YOL018c (TLG2) of Saccharomyces cerevisiae encodes a protein that belongs to the syntaxin protein family. The proteins of this family, t-SNAREs, are present on target organelles and are thought to participate in the specific interaction between vesicles and acceptor membranes in intracellular membrane trafficking. TLG2 is not an essential gene, and its deletion does not cause defects in the secretory pathway. However, its deletion in cells lacking the vacuolar ATPase subunit Vma2p leads to loss of viability, suggesting that Tlg2p is involved in endocytosis. In tlg2Delta cells, internalization was normal for two endocytic markers, the pheromone alpha-factor and the plasma membrane uracil permease. In contrast, degradation of alpha-factor and uracil permease was delayed in tlg2Delta cells. Internalization of positively charged Nanogold shows that the endocytic pathway is perturbed in the mutant, which accumulates Nanogold in primary endocytic vesicles and shows a greatly reduced complement of early endosomes. These results strongly suggest that Tlg2p is a t-SNARE involved in early endosome biogenesis.