protein folding and processing in ER

protein folding and processing in ER - S protein...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
protein folding and processing in ER translocation into lumen as unfolded polypeptide chain folding : (like for proteins synthesized in cytosol) assisted by molecular chaperones especially from the HSP70 family (HSP70 means h eat s hock p rotein of about 70 kD, protein family is always present but shows higher expression during stress that leads to increased protein denaturation like elevated temperatures) formation of disulfide bonds : facilitated by protein disulfide isomerase (disulfide bonds possible because oxidizing athmosphere in ER, different from cytosol where athmoshere is reducing and therefore reduced group -SH instead of oxidized group -S-
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: S-) protein glycosylation : means addition of sugar residues. Specifically, a complex oligosaccharide is added to an asparagine side chain ( N-linked glycosylation , because at -NH2 group of asparagine) in consensus sequence Asn-X-Ser/Thr (X stands for any amino acid residue). From ER to Golgi : transport in vesicles via bulk flow (no signal necessary) instead signal sequence necessary for retention in ER (most commonly Lys-Asp-Glu-Leu or KDEL at carboxyl terminus, KDEL stands for the 4 amino acids in their single letter code) membrane-bound proteins are directly retained, soluble proteins are retrieved from Golgi...
View Full Document

This document was uploaded on 11/03/2011 for the course BIOLOGY MCB2010 at Broward College.

Ask a homework question - tutors are online