6n85
From Proteopedia
Resistance to inhibitors of cholinesterase 8A (Ric8A) protein in complex with MBP-tagged transducin-alpha residues 327-350
Structural highlights
Function[RIC8A_BOVIN] Guanine nucleotide exchange factor (GEF), which can activate some, but not all, G-alpha proteins. Able to activate GNAI1, GNAO1 and GNAQ, but not GNAS by exchanging bound GDP for free GTP. Involved in regulation of microtubule pulling forces during mitotic movement of chromosomes by stimulating G(i)-alpha protein, possibly leading to release G(i)-alpha-GTP and NuMA proteins from the NuMA-GPSM2-G(i)-alpha-GDP complex. Also acts as an activator for G(q)-alpha (GNAQ) protein by enhancing the G(q)-coupled receptor-mediated ERK activation (By similarity). [MALE_ECO57] Involved in the high-affinity maltose membrane transport system MalEFGK. Initial receptor for the active transport of and chemotaxis toward maltooligosaccharides (By similarity). Publication Abstract from PubMedResistance to inhibitors of cholinesterase 8A (Ric8A) is an essential regulator of G protein alpha-subunits (Galpha), acting as a guanine nucleotide exchange factor and a chaperone. We report two crystal structures of Ric8A, one in the apo form and the other in complex with a tagged C-terminal fragment of Galpha. These structures reveal two principal domains of Ric8A: an armadillo-fold core and a flexible C-terminal tail. Additionally, they show that the Galpha C-terminus binds to a highly-conserved patch on the concave surface of the Ric8A armadillo-domain, with selectivity determinants residing in the Galpha sequence. Biochemical analysis shows that the Ric8A C-terminal tail is critical for its stability and function. A model of the Ric8A/Galpha complex derived from crosslinking mass spectrometry and molecular dynamics simulations suggests that the Ric8A C-terminal tail helps organize the GTP-binding site of Galpha. This study lays the groundwork for understanding Ric8A function at the molecular level. Structural underpinnings of Ric8A function as a G-protein alpha-subunit chaperone and guanine-nucleotide exchange factor.,Srivastava D, Gakhar L, Artemyev NO Nat Commun. 2019 Jul 12;10(1):3084. doi: 10.1038/s41467-019-11088-x. PMID:31300652[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Bovin | Human | Large Structures | Artemyev, N O | Gakhar, L | Srivastava, D | Armadillo repeat | Chaperone | G alpha | Mbp | Ric8a
