Active and specific recruitment of a soluble cargo protein for endoplasmic reticulum exit in the absence of functional COPII component Sec24p
| Autor: | Netta Fatal, Leena Karhinen, Eija Jokitalo, Marja Makarow |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Saccharomyces cerevisiae Proteins
Saccharomyces cerevisiae Vesicular Transport Proteins Biology Endoplasmic Reticulum 03 medical and health sciences Protein structure COPII Heat-Shock Proteins Glycoproteins 030304 developmental biology 0303 health sciences Endoplasmic reticulum 030302 biochemistry & molecular biology Membrane Proteins Membrane Transport Proteins Cell Biology COPI biology.organism_classification Fusion protein Protein Structure Tertiary Transport protein Cell biology Microscopy Electron Protein Transport Solubility Biochemistry Mutation |
| Zdroj: | Journal of Cell Science. 117:1665-1673 |
| ISSN: | 1477-9137 0021-9533 |
| DOI: | 10.1242/jcs.01019 |
| Popis: | Exit of proteins from the yeast endoplasmic reticulum (ER) is thought to occur in vesicles coated by four proteins, Sec13p, Sec31p, Sec23p and Sec24p, which assemble at ER exit sites to form the COPII coat. Sec13p may serve a structural function, whereas Sec24p has been suggested to operate in selection of cargo proteins into COPII vesicles. We showed recently that the soluble glycoprotein Hsp150 exited the ER in the absence of Sec13p function. Here we show that its ER exit did not require functional Sec24p. Hsp150 was secreted to the medium in a sec24-1 mutant at restrictive temperature 37°C, while cell wall invertase and vacuolar carboxypeptidase Y remained in the ER. The determinant guiding Hsp150 to this transport route was mapped to the C-terminal domain of 114 amino acids by deletion analysis, and by an HRP fusion protein-based EM technology adapted here for yeast. This domain actively mediated ER exit of Sec24p-dependent invertase in the absence of Sec24p function. However, the domain was entirely dispensable for ER exit when Sec24p was functional. The Sec24p homolog Sfb2p was shown not to compensate for nonfunctional Sec24p in ER exit of Hsp150. Our data show that a soluble cargo protein, Hsp150, is selected actively and specifically to budding sites lacking normal Sec24p by a signature residing in its C-terminal domain. |
| Databáze: | OpenAIRE |
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