7obq
SRP-SR at the distal site conformation
Structural highlights
FunctionSRP19_CANLF Component of the signal recognition particle (SRP) complex, a ribonucleoprotein complex that mediates the cotranslational targeting of secretory and membrane proteins to the endoplasmic reticulum (ER) (PubMed:6413076, PubMed:6938958). Binds directly to 7SL RNA (PubMed:6413076). Mediates binding of SRP54 to the SRP complex (PubMed:6413076).[1] [2] Publication Abstract from PubMedCo-translational protein targeting to membranes by the signal recognition particle (SRP) is a universally conserved pathway from bacteria to humans. In mammals, SRP and its receptor (SR) have many additional RNA features and protein components compared to the bacterial system, which were recently shown to play regulatory roles. Due to its complexity, the mammalian SRP targeting process is mechanistically not well understood. In particular, it is not clear how SRP recognizes translating ribosomes with exposed signal sequences and how the GTPase activity of SRP and SR is regulated. Here, we present electron cryo-microscopy structures of SRP and SRP.SR in complex with the translating ribosome. The structures reveal the specific molecular interactions between SRP and the emerging signal sequence and the elements that regulate GTPase activity of SRP.SR. Our results suggest the molecular mechanism of how eukaryote-specific elements regulate the early and late stages of SRP-dependent protein targeting. Molecular mechanism of cargo recognition and handover by the mammalian signal recognition particle.,Jomaa A, Eitzinger S, Zhu Z, Chandrasekar S, Kobayashi K, Shan SO, Ban N Cell Rep. 2021 Jul 13;36(2):109350. doi: 10.1016/j.celrep.2021.109350. PMID:34260909[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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