{PDOC51470} {PS51470; FG_GAP} {BEGIN} ************************* * FG-GAP repeat profile * ************************* Integrins are cell adhesion receptors that transmit bidirectional signals across the plasma membrane and link the extracellular environment to the actin cytoskeleton [1]. Integrins are formed from alpha and beta subunits. The N-terminal region of alpha subunits contains seven 60 amino acids sequence repeats which fold into a beta-propeller domain [2]. Integrins bind ligands at the interface between the alpha subunit beta-propeller domain and beta subunit I domain [3]. These domains associate over a large interface to form the integrin head. The seven FG-GAP repeat domain is also found in the enzyme phosphatidylinositol phospholipase D. The crystal structure of the beta-propeller FG-GAP domain of integrin alpha V shows that the domain consists of seven radially arranged "blades" each formed from a four-stranded antiparallel sheet (ABCD) (see ) [4]. The inner strand (strand A) of each blade lines the channel at the center of the propeller, and strand D of the next repeat forming the outer edge of the blade. The beta-propeller is circularized by juxtaposition of the C7 and D1 strands. Several Ca2+-binding sites are found in hairpin loops connecting beta strands. The profile we developed covers strand B,C,D and A of the FG-GAP repeat. -Sequences known to belong to this class detected by the profile: ALL. -Other sequence(s) detected in Swiss-Prot: NONE. -Last update: December 2009 / First entry. [ 1] Springer T.A. "Folding of the N-terminal, ligand-binding region of integrin alpha-subunits into a beta-propeller domain." Proc. Natl. Acad. Sci. U.S.A. 94:65-72(1997). PubMed=8990162 [ 2] Loftus J.C., Smith J.W., Ginsberg M.H. "Integrin-mediated cell adhesion: the extracellular face." J. Biol. Chem. 269:25235-25238(1994). PubMed=7929213 [ 3] Xiong J.P., Stehle T., Zhang R., Joachimiak A., Frech M., Goodman S.L., Arnaout M.A. "Crystal structure of the extracellular segment of integrin alpha Vbeta3 in complex with an Arg-Gly-Asp ligand." Science 296:151-155(2002). PubMed=11884718; DOI=10.1126/science.1069040 [ 4] Xiong J.P., Stehle T., Diefenbach B., Zhang R., Dunker R., Scott D.L., Joachimiak A., Goodman S.L., Arnaout M.A. "Crystal structure of the extracellular segment of integrin alpha Vbeta3." Science 294:339-345(2001). PubMed=11546839; DOI=10.1126/science.1064535 -------------------------------------------------------------------------------- PROSITE is copyrighted by the SIB Swiss Institute of Bioinformatics and distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives (CC BY-NC-ND 4.0) License, see https://prosite.expasy.org/prosite_license.html -------------------------------------------------------------------------------- {END}