This family of proteins are membrane localised chaperones that are required for correct plasma membrane localisation of amino acid permeases (AAPs) (PUBMED:15623581). Shr3 prevents AAPs proteins from aggregating and assists in their correct folding. In the absence of Shr3, AAPs are retained in the ER.
This family of proteins are membrane localised chaperones that are required for correct plasma membrane localisation of amino acid permeases (AAPs) [ (PUBMED:15623581) ]. Shr3 prevents AAPs proteins from aggregating and assists in their correct folding. In the absence of Shr3, AAPs are retained in the ER.
Family alignment:
There are 598 SHR3_chaperone domains in 597 proteins in SMART's nrdb database.
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Evolution (species in which this domain is found)
Taxonomic distribution of proteins containing SHR3_chaperone domain.
This tree includes only several representative species. The complete taxonomic breakdown of all proteins with SHR3_chaperone domain is also avaliable.
Click on the protein counts, or double click on taxonomic names to display all proteins containing SHR3_chaperone domain in the selected taxonomic class.
Specialized membrane-localized chaperones prevent aggregation of polytopic proteins in the ER.
J Cell Biol. 2005; 168: 79-88
Display abstract
The integral endoplasmic reticulum (ER) membrane protein Shr3p is required for proper plasma membrane localization of amino acid permeases (AAPs) in yeast. In the absence of Shr3p AAPs are uniquely retained in the ER with each of their twelve membrane-spanning segments correctly inserted in the membrane. Here, we show that the membrane domain of Shr3p specifically prevents AAPs from aggregating, and thus, plays a critical role in assisting AAPs to fold and correctly attain tertiary structures required for ER exit. Also, we show that the integral ER proteins, Gsf2p, Pho86p, and Chs7p, function similarly to Shr3p. In cells individually lacking one of these components only their cognate substrates, hexose transporters, phosphate transporters, and chitin synthase-III, respectively, aggregate and consequently fail to exit the ER membrane. These findings indicate that polytopic membrane proteins depend on specialized membrane-localized chaperones to prevent inappropriate interactions between membrane-spanning segments as they insert and fold in the lipid bilayer of the ER membrane.
Links (links to other resources describing this domain)
