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Rho GTPase activating protein 26
Protein ARHGAP26 PDB 1f7c.png
PDB rendering based on 1f7c.
Available structures
PDB Ortholog search: PDBe, RCSB
External IDs OMIM605370 MGI1918552 HomoloGene36349 GeneCards: ARHGAP26 Gene
RNA expression pattern
PBB GE ARHGAP26 205068 s at tn.png
PBB GE ARHGAP26 205069 s at tn.png
PBB GE ARHGAP26 215955 x at tn.png
More reference expression data
Species Human Mouse
Entrez 23092 71302
Ensembl ENSG00000145819 ENSMUSG00000036452
UniProt Q9UNA1 Q6ZQ82
RefSeq (mRNA) NM_001135608 NM_175164
RefSeq (protein) NP_001129080 NP_780373
Location (UCSC) Chr 5:
142.15 – 142.61 Mb
Chr 18:
38.6 – 39.38 Mb
PubMed search [1] [2]

Rho GTPase activating protein 26 (ARHGAP26) also known as GTPase Regulator Associated with Focal Adhesion Kinase (GRAF) is a protein that in humans is encoded by the ARHGAP26 gene.[1][2][3]


GRAF is a multidomain protein that is necessary for the CLIC/GEEC endocytic pathway,[4] the most prevalent clathrin-independent endocytic pathway discovered to date. By virtue of an N-terminal BAR domain, GRAF1 sculpts the endocytic membranes of this pathway into 40 nm diameter tubules and vesicles that allow uptake of extracellular fluid, GPI-linked proteins and certain bacterial exotoxins into cells. The role of dynamin in the CLIC/GEEC pathway is controversial, but GRAF1 interacts strongly with this protein and acute inhibition of dynamin action abrogates CLIC/GEEC endocytosis. There are several members of the GRAF family of proteins, including GRAF2, GRAF3, and oligophrenin, all of which likely playing similar roles during clathrin-independent endocytic events. Mutations of both GRAF1 and oligophrenin are strongly implicated in causing human disease (leukaemia and mental retardation, respectively). Recently, autoantibodies to ARHGAP26 have been implicated in autoimmune cerebellar ataxia.[5][6][7]


ARHGAP26 has been shown to interact with PKN3.[8]


  1. ^ "Entrez Gene: ARHGAP26 Rho GTPase activating protein 26". 
  2. ^ Hildebrand JD, Taylor JM, Parsons JT (June 1996). "An SH3 domain-containing GTPase-activating protein for Rho and Cdc42 associates with focal adhesion kinase". Mol. Cell. Biol. 16 (6): 3169–78. PMC 231310. PMID 8649427. 
  3. ^ Taylor JM, Macklem MM, Parsons JT (January 1999). "Cytoskeletal changes induced by GRAF, the GTPase regulator associated with focal adhesion kinase, are mediated by Rho". J. Cell. Sci. 112 ( Pt 2): 231–42. PMID 9858476. 
  4. ^ Lundmark R, Doherty GJ, Howes MT, Cortese K, Vallis Y, Parton RG et al. (November 2008). "The GTPase-activating protein GRAF1 regulates the CLIC/GEEC endocytic pathway". Curr. Biol. 18 (22): 1802–8. doi:10.1016/j.cub.2008.10.044. PMC 2726289. PMID 19036340. 
  5. ^ Jarius S, Wandinger KP, Horn S, Heuer H, Wildemann B (Mar 2012). "A new Purkinje cell antibody (anti-Ca) associated with subacute cerebellar ataxia: immunological characterization". J Neuroinflammation 7 (7): 21. doi:10.1186/1742-2094-7-21. PMID 20226058.  Check date values in: |year= / |date= mismatch (help)
  6. ^ Jarius S, Martínez-García P, Hernandez AL, Brase JC, Borowski K, Regula JU et al. (Jan 2013). "Two new cases of anti-Ca (anti-ARHGAP26/GRAF) autoantibody-associated cerebellar ataxia". J Neuroinflammation 10 (10): 7. doi:10.1186/1742-2094-10-7. PMID 23320754. 
  7. ^ Doss S, Nümann A, Ziegler A, Siebert E, Borowski K, Stöcker W et al. (15 Feb 2014). "Anti-Ca/anti-ARHGAP26 antibodies associated with cerebellar atrophy and cognitive decline". J. Neuroimmunol. 267 (1-2): 102–4. doi:10.1016/j.jneuroim.2013.10.010. PMID 24439423. 
  8. ^ Shibata H, Oishi K, Yamagiwa A, Matsumoto M, Mukai H, Ono Y (2001). "PKNbeta interacts with the SH3 domains of Graf and a novel Graf related protein, Graf2, which are GTPase activating proteins for Rho family". J. Biochem. 130 (1): 23–31. doi:10.1093/oxfordjournals.jbchem.a002958. PMID 11432776. 

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