2c5d

From Proteopedia

Revision as of 17:00, 18 December 2007

STRUCTURE OF A MINIMAL GAS6-AXL COMPLEX

Overview

Receptor tyrosine kinases of the Axl family are activated by the vitamin, K-dependent protein Gas6. Axl signalling plays important roles in cancer, spermatogenesis, immunity, and platelet function. The crystal structure at, 3.3 A resolution of a minimal human Gas6/Axl complex reveals an assembly, of 2:2 stoichiometry, in which the two immunoglobulin-like domains of the, Axl ectodomain are crosslinked by the first laminin G-like domain of Gas6, with no direct Axl/Axl or Gas6/Gas6 contacts. There are two distinct, Gas6/Axl contacts of very different size, both featuring interactions, between edge beta-strands. Structure-based mutagenesis, protein binding, assays and receptor activation experiments demonstrate that both the major, and minor Gas6 binding sites are required for productive transmembrane, signalling. Gas6-mediated Axl dimerisation is likely to occur in two, steps, with a high-affinity 1:1 Gas6/Axl complex forming first. Only the, minor Gas6 binding site is highly conserved in the other Axl family, receptors, Sky/Tyro3 and Mer. Specificity at the major contact is, suggested to result from the segregation of charged and apolar residues to, opposite faces of the newly formed beta-sheet.

About this Structure

2C5D is a Protein complex structure of sequences from Homo sapiens with CA, NI and SO4 as ligands. Active as Transferred entry: 2.7.10.1 and 2.7.10.2, with EC number 2.7.1.112 Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Structural basis for Gas6-Axl signalling., Sasaki T, Knyazev PG, Clout NJ, Cheburkin Y, Gohring W, Ullrich A, Timpl R, Hohenester E, EMBO J. 2006 Jan 11;25(1):80-7. Epub 2005 Dec 15. PMID:16362042

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