Protein molecular chaperone role

Welch, W.J. (1991). The role of heat shock proteins as molecular chaperones Curr. Opin. Cell Biol. 3, 1033-1038. 

Frydman J Folding of newly translated proteins in vivo The role of molecular chaperones. Annu Rev Biochem 2001 70 603. Radord S Protein folding Progress made and promises ahead. 

Exit from the ER may be the rate-limiting step in the secretory pathway. In this context, it has been found that certain proteins play a role in the assembly or proper folding of other proteins without themselves being components of the latter. Such proteins are called molecular chaperones a number of important properties of these proteins are listed in Table 46—5, and the names of some of particular importance in the ER are listed in Table 46-6. Basically, they stabilize unfolded... 

In addition to its role as the P-subunit of PHY, PDI acts independently by catalysing thiol/protein disulphide interchange. The role of PDI as the P-subunit in prolyl 4-hydroxylase is not related to its disulphide isomerase activity and experiments where the vertebrate PDI was mutated in both thioredoxin-like active domains had no effect on tetramer assembly (Vuori et al., 1992). PDI appears to function as a molecular chaperone, retaining the a-subunits in the correct catalytically active, non-aggregated form in the ER-lumen (John et al, 1993). Dissociation of the P-subunits results in insoluble aggregates of the a-subunits, analogous to a-subunits expressed in the absence of PDI. An additional function of PDI in the complex is to maintain the ER luminal location of the a-subunits, since deletion of the ER retention signal from PDI results in the secretion of the complex (Vuori et al., 1992). 

Stuart R (2002) Insertion of proteins into the inner membrane of mitochondria the role of the Oxal complex. Biochim Biophys Acta 1592 79-87 Stuart RA, Cyr DM, Craig EA, Neupert W (1994) Mitochondrial molecular chaperones their role in protein translocation. Trends Biochem Sci 19 87-92 Sutak R et al. (2004) Mitochondrial-type assembly of FeS centers in the hydrogenosomes of the amitochondriate eukaryote Trichomonas vaginalis. Proc Natl Acad Sci USA 101 10368-10373... 

Georgopolous, C., and Welch, W. 1993. Role of major heat shock proteins as molecular chaperones. Annu. Rev. Cell Biol. 9 601-635. 

Agashe.V. R., Haetl, F. U. (2000). Roles of molecular chaperones in cytoplasmic protein folding. Semin. Cell Dev. Biol. 11, 15-25. 

A growing body of evidence indicates that in addition to a targeting element, membrane translocation also requires that the secretory protein assumes a loosely folded or translocation-competent state. The focus of this review is the role that SecB and other molecular chaperones play in sponsoring efficient protein secretion in E. coli. 

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