A role for Tlg1p in the transport of proteins within the Golgi apparatus of Saccharomyces cerevisiae
| Autor: | Wanjin Hong, Anthony C.B. Lim, Jing Xu, John G. S. Coe |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Glycoside Hydrolases Molecular Sequence Data Vesicular Transport Proteins Golgi Apparatus Vacuole Saccharomyces cerevisiae Article Fungal Proteins symbols.namesake Syntaxin Cloning Molecular Molecular Biology Adenosine Triphosphatases Fungal protein biology Base Sequence beta-Fructofuranosidase Membrane transport protein Qa-SNARE Proteins Endoplasmic reticulum Temperature Membrane Proteins Membrane Transport Proteins Biological Transport Cell Biology Intracellular Membranes Golgi apparatus Qb-SNARE Proteins Cell biology Vesicular transport protein Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins Biochemistry Mutation Vacuoles biology.protein symbols Carrier Proteins Cell Division |
| Zdroj: | Molecular biology of the cell. 10(7) |
| ISSN: | 1059-1524 |
| Popis: | Members of the syntaxin protein family participate in the docking–fusion step of several intracellular vesicular transport events. Tlg1p has been identified as a nonessential protein required for efficient endocytosis as well as the maintenance of normal levels of trans-Golgi network proteins. In this study we independently describe Tlg1p as an essential protein required for cell viability. Depletion of Tlg1p in vivo causes a defect in the transport of the vacuolar protein carboxypeptidase Y through the early Golgi. Temperature-sensitive (ts) mutants of Tlg1p also accumulate the endoplasmic reticulum/cis-Golgi form of carboxypeptidase Y at the nonpermissive temperature (38°C) and exhibit underglycosylation of secreted invertase. Overexpression of Tlg1p complements the growth defect of vti1-11 at the nonpermissive temperature, whereas incomplete complementation was observed with vti1-1, further suggesting a role for Tlg1p in the Golgi apparatus. Overexpression of Sed5p decreases the viability of tlg1 ts mutants compared with wild-type cells, suggesting that tlg1 ts mutants are more susceptible to elevated levels of Sed5p. Tlg1p is able to bind His6-tagged Sec17p (yeast α-SNAP) in a dose-dependent manner and enters into a SNARE complex with Vti1p, Tlg2p, and Vps45p. Morphological analyses by electron microscopy reveal that cells depleted of Tlg1p or tlg1 ts mutants incubated at the restrictive temperature accumulate 40- to 50-nm vesicles and experience fragmentation of the vacuole. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|