PROSITE documentation PDOC51470
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 α and β subunits. The N-terminal region of α subunits contains seven 60 amino acids sequence repeats which fold into a β-propeller domain [2]. Integrins bind ligands at the interface between the α subunit β-propeller domain and β 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 β-propeller FG-GAP domain of integrin α V shows that the domain consists of seven radially arranged "blades" each formed from a four-stranded antiparallel sheet (ABCD) (see <PDB:1JV2>) [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 β-propeller is circularized by juxtaposition of the C7 and D1 strands. Several Ca2+-binding sites are found in hairpin loops connecting β strands.

The profile we developed covers strand B,C,D and A of the FG-GAP repeat.

Last update:

December 2009 / First entry.


Technical section

PROSITE method (with tools and information) covered by this documentation:

FG_GAP, PS51470; FG-GAP repeat profile  (MATRIX)


1AuthorsSpringer T.A.
TitleFolding of the N-terminal, ligand-binding region of integrin alpha-subunits into a beta-propeller domain.
SourceProc. Natl. Acad. Sci. U.S.A. 94:65-72(1997).
PubMed ID8990162

2AuthorsLoftus J.C. Smith J.W. Ginsberg M.H.
TitleIntegrin-mediated cell adhesion: the extracellular face.
SourceJ. Biol. Chem. 269:25235-25238(1994).
PubMed ID7929213

3AuthorsXiong J.P. Stehle T. Zhang R. Joachimiak A. Frech M. Goodman S.L. Arnaout M.A.
TitleCrystal structure of the extracellular segment of integrin alpha Vbeta3 in complex with an Arg-Gly-Asp ligand.
SourceScience 296:151-155(2002).
PubMed ID11884718

4AuthorsXiong J.P. Stehle T. Diefenbach B. Zhang R. Dunker R. Scott D.L. Joachimiak A. Goodman S.L. Arnaout M.A.
TitleCrystal structure of the extracellular segment of integrin alpha Vbeta3.
SourceScience 294:339-345(2001).
PubMed ID11546839

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