Structural highlights
Function
[SRPR_YEAST] Component of the SRP (signal recognition particle) receptor. Ensures, in conjunction with the signal recognition particle, the correct targeting of the nascent secretory proteins to the endoplasmic reticulum membrane system. GTP hydrolysis may enhance the fidelity of and provide unidirectionality to the targeting reaction. It is important but not essential for cell growth. May be directly involved in mitochondrial protein import.[1] [SRPB_YEAST] Component of the SRP (signal recognition particle) receptor. Ensures, in conjunction with the signal recognition particle, the correct targeting of the nascent secretory proteins to the endoplasmic reticulum membrane system. Has GTPase activity. May mediate the membrane association of SRPR.
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
Protein translocation across and insertion into membranes is a process essential to all life forms. In higher eukaryotes, this process is initiated by targeting the translating ribosome to the endoplasmic reticulum via the signal recognition particle (SRP) and its membrane-associated heterodimeric receptor (SR). This targeting step is regulated by three G proteins, SRP54, SR alpha, and SR beta, which act in concert. Little is known about the regulatory role of SR beta. Here, we present the 1.7 A crystal structure of the SR beta-GTP subunit in complex with the interaction domain of SR alpha. Strikingly, the binding interface overlaps largely with the switch 1 region of SR beta. This finding, together with additional biochemical data, shows that the eukaryotic SR is a conditional and not an obligate heterodimer. The results suggest that the GTP/GDP switch cycle of SR beta functions as a regulatory switch for the receptor dimerization. We discuss the implications for the translocation pathway.
Structural basis for the function of the beta subunit of the eukaryotic signal recognition particle receptor.,Schwartz T, Blobel G Cell. 2003 Mar 21;112(6):793-803. PMID:12654246[2]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Ogg SC, Poritz MA, Walter P. Signal recognition particle receptor is important for cell growth and protein secretion in Saccharomyces cerevisiae. Mol Biol Cell. 1992 Aug;3(8):895-911. PMID:1327299
- ↑ Schwartz T, Blobel G. Structural basis for the function of the beta subunit of the eukaryotic signal recognition particle receptor. Cell. 2003 Mar 21;112(6):793-803. PMID:12654246
