PROSITE documentation PDOC50108
CRIB domain profile


Many putative downstream effectors of the small GTPases Cdc42 and Rac contain a GTPase binding domain (GBD), also called p21 binding domain (PBD), which has been shown to specifically bind the GTP bound form of Cdc42 or Rac, with a preference for Cdc42 [1,2]. The most conserved region of GBD/PBD domains is the N-terminal Cdc42/Rac interactive binding motif (CRIB), which consists of about 16 amino acids with the consensus sequence I-S-x-P-x(2,4)-F-x-H-x(2)-H-V-G [3]. Although the CRIB motif is necessary for the binding to Cdc42 and Rac, it is not sufficient to give high-affinity binding [4,5]. A less well conserved inhibitory switch (IS) domain responsible for maintaining the proteins in a basal (autoinhibited) state is located C-terminaly of the CRIB-motif [6,7,8].

GBD domains can adopt related but distinct folds depending on context. Although GBD domains are largely unstructured in the free state, the IS domain forms an N-terminal β hairpin that immediately follows the conserved CRIB motif and a central bundle of three α helices in the autoinhibited state. The interaction between GBD domains and their respective G proteins leads to the formation of a high-affinity complex in which unstructured regions of both the effector and the G protein become rigid. CRIB motifs from various GBD domains interact with Cdc42 in a similar manner, forming an intermolecular β-sheet with strand β-2 of Cdc42. Outside the CRIB motif, the C-termini of the various GBD domains are very divergent and show variation in their mode of binding to Cdc42, perhaps determining the specificity of the interaction. Binding of Cdc42 or Rac to the GBD domain causes a dramatic conformational change, refolding part of the IS domain and unfolding the rest [4,6,7,8,9,10].

Some proteins known to contain a CRIB domain are listed below:

  • Mammalian activated Cdc42-associated kinases (ACKs), nonreceptor tyrosine kinases implicated in integrin-coupled pathways.
  • Mammalian p21-activated kinases (PAK1 to PAK4), serine/threonine kinases that modulate cytoskeletal assembly and activate MAP-kinase pathways.
  • Mammalian Wiskott-Aldrich Symdrom Proteins (WASPs), non-kinase proteins involved in the organization of the actin cytoskeleton.
  • Yeast STE20 and CLA4, the homologues of mammalian PAKs. STE20 is involved in the mating/pheromone MAP kinase cascade.

The profile we developed covers the entire CRIB domain.

Last update:

June 2002 / Profile changed.


Technical section

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

CRIB, PS50108; CRIB domain profile  (MATRIX)


1AuthorsManser E. Leung T. Salihuddin H. Zhao Z.-S. Lim L.
TitleA brain serine/threonine protein kinase activated by Cdc42 and Rac1.
SourceNature 367:40-46(1994).
PubMed ID8107774

2AuthorsSymons M. Derry J.M.J. Karlak B. Jiang S. Lemahieu V. Mccormick F. Francke U. Abo A.
TitleWiskott-Aldrich syndrome protein, a novel effector for the GTPase CDC42Hs, is implicated in actin polymerization.
SourceCell 84:723-734(1996).
PubMed ID8625410

3AuthorsBurbelo P.D. Drechsel D. Hall A.
TitleA conserved binding motif defines numerous candidate target proteins for both Cdc42 and Rac GTPases.
SourceJ. Biol. Chem. 270:29071-29074(1995).
PubMed ID7493928

4AuthorsRudolph M.G. Bayer P. Abo A. Kuhlmann J. Vetter I.R. Wittinghofer A.
TitleThe Cdc42/Rac interactive binding region motif of the Wiskott Aldrich syndrome protein (WASP) is necessary but not sufficient for tight binding to Cdc42 and structure formation.
SourceJ. Biol. Chem. 273:18067-18076(1998).
PubMed ID9660763

5AuthorsThompson G. Owen D. Chalk P.A. Lowe P.N.
TitleDelineation of the Cdc42/Rac-binding domain of p21-activated kinase.
SourceBiochemistry 37:7885-7891(1998).
PubMed ID9601050

6AuthorsKim A.S. Kakalis L.T. Abdul-Manan N. Liu G.A. Rosen M.K.
TitleAutoinhibition and activation mechanisms of the Wiskott-Aldrich syndrome protein.
SourceNature 404:151-158(2000).
PubMed ID10724160

7AuthorsLei M. Lu W. Meng W. Parrini M.-C. Eck M.J. Mayer B.J. Harrison S.C.
TitleStructure of PAK1 in an autoinhibited conformation reveals a multistage activation switch.
SourceCell 102:387-397(2000).
PubMed ID10975528

8AuthorsHoffman G.R. Cerione R.A.
TitleFlipping the switch: the structural basis for signaling through the CRIB motif.
SourceCell 102:403-406(2000).
PubMed ID10966102

9AuthorsMott H.R. Owen D. Nietlispach D. Lowe P.N. Manser E. Lim L. Laue E.D.
TitleStructure of the small G protein Cdc42 bound to the GTPase-binding domain of ACK.
SourceNature 399:384-388(1999).
PubMed ID10360579

10AuthorsMorreale A. Venkatesan M. Mott H.R. Owen D. Nietlispach D. Lowe P.N. Laue E.D.
SourceNat. Struct. Biol. 7:384-388(2000).

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