Selective Protein Exit from Yeast Endoplasmic Reticulum in Absence of Functional COPII Coat Component Sec13p
AUTOR(ES)
Fatal, Netta
FONTE
The American Society for Cell Biology
RESUMO
Sec13p has been thought to be an essential component of the COPII coat, required for exit of proteins from the yeast endoplasmic reticulum (ER). We show herein that normal function of Sec13p was not required for ER exit of the Hsp150 glycoprotein. Hsp150 was secreted to the medium under restrictive conditions in a sec13-1 mutant. The COPII components Sec23p and Sec31p and the GTP/GDP exchange factor Sec12p were required in functional form for secretion of Hsp150. Hsp150 leaves the ER in the absence of retrograde COPI traffic, and the responsible determinant is a peptide repeated 11 times in the middle of the Hsp150 sequence. Herein, we localized the sorting determinant for Sec13p-independent ER exit to the C-terminal domain. Sec13p-dependent invertase left the ER in the absence of normal Sec13p function, when fused to the C-terminal domain of Hsp150, demonstrating that this domain contained an active mediator of Sec13p-independent secretion. Thus, Hsp150 harbors two different signatures that regulate its ER exit. Our data show that transport vesicles lacking functional Sec13p can carry out ER-to-Golgi transport, but select only specific cargo protein(s) for ER exit.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=138621Documentos Relacionados
- Sec31 encodes an essential component of the COPII coat required for transport vesicle budding from the endoplasmic reticulum.
- The mammalian homolog of yeast Sec13p is enriched in the intermediate compartment and is essential for protein transport from the endoplasmic reticulum to the Golgi apparatus.
- Structural and functional dissection of Sec62p, a membrane-bound component of the yeast endoplasmic reticulum protein import machinery.
- Specific interaction of the yeast cis-Golgi syntaxin Sed5p and the coat protein complex II component Sec24p of endoplasmic reticulum-derived transport vesicles
- Sec62p, A Component of the Endoplasmic Reticulum Protein Translocation Machinery, Contains Multiple Binding Sites for the Sec-Complex