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Gene Review

RACGAP1  -  Rac GTPase activating protein 1

Homo sapiens

Synonyms: CYK4, HsCYK-4, ID-GAP, KIAA1478, MGCRACGAP, ...
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Disease relevance of RACGAP1


High impact information on RACGAP1

  • (2003) establish an important connection between three regulatory molecules that coordinate this process, showing that the mitotic kinase aurora B phosphorylates MgcRacGAP to convert it to a GAP for RhoA, a small GTPase that drives cytokinesis [3].
  • Recent work has identified nucleotide-exchange factors for Ral-GTPases as the newest members of the set of putative Ras 'effector molecules'. This new work has also detected two potential downstream targets of Ral proteins, a novel CDC42/Rac GTPase-activating protein and a phospholipase D [4].
  • Using permeabilized cells, we find that nuclear translocation of purified p-STAT5A is dependent on the addition of GTP-bound Rac1, MgcRacGAP, importin alpha, and importin beta. p-STAT3 also enters the nucleus via this transport machinery, and mutant STATs lacking the MgcRacGAP binding site do not enter the nucleus even after phosphorylation [5].
  • We show that Rac1 and a GTPase-activating protein, MgcRacGAP, bind directly to p-STAT5A and are required to promote its nuclear translocation [5].
  • We conclude that GTP-bound Rac1 and MgcRacGAP function as a nuclear transport chaperone for activated STATs [5].

Biological context of RACGAP1


Anatomical context of RACGAP1


Associations of RACGAP1 with chemical compounds

  • Unlike apoptotic blebbing, MgcRacGAP R386A-induced blebbing was not inhibited by the ROCK inhibitor Y-27632, suggesting that MgcRacGAP regulates cortical activity during cytokinesis through a novel signaling pathway [1].

Physical interactions of RACGAP1

  • Two-hybrid and in vitro binding assays demonstrate that MgcRacGAP stably interacts through its NH(2)-terminal domain with the Tat1 COOH-terminal region [11].

Regulatory relationships of RACGAP1

  • We conclude that MgcRacGAP controls the initiation of cytokinesis by regulating ECT2, which in turn induces the assembly of the contractile ring and triggers the ingression of the cleavage furrow [13].
  • In reporter assays, the wild-type MgcRacGAP enhanced transcriptional activation of STAT3 while a GAP-domain deletion mutant (DeltaGAP) did not significantly enhance it, suggesting that the GAP domain was required for enhancement of STAT3-dependent transcription [10].
  • However, how MgcRacGAP enhanced IL-6-induced differentiation remained elusive [10].
  • MgcRacGAP regulates cortical activity through RhoA during cytokinesis [1].

Other interactions of RACGAP1


  1. MgcRacGAP regulates cortical activity through RhoA during cytokinesis. Lee, J.S., Kamijo, K., Ohara, N., Kitamura, T., Miki, T. Exp. Cell Res. (2004) [Pubmed]
  2. Essential role for Rac in heregulin beta1 mitogenic signaling: a mechanism that involves epidermal growth factor receptor and is independent of ErbB4. Yang, C., Liu, Y., Lemmon, M.A., Kazanietz, M.G. Mol. Cell. Biol. (2006) [Pubmed]
  3. Closing the GAP: a role for a RhoA GAP in cytokinesis. Maddox, A.S., Oegema, K. Mol. Cell (2003) [Pubmed]
  4. Evidence for a Ras/Ral signaling cascade. Feig, L.A., Urano, T., Cantor, S. Trends Biochem. Sci. (1996) [Pubmed]
  5. Rac1 and a GTPase-activating protein, MgcRacGAP, are required for nuclear translocation of STAT transcription factors. Kawashima, T., Bao, Y.C., Nomura, Y., Moon, Y., Tonozuka, Y., Minoshima, Y., Hatori, T., Tsuchiya, A., Kiyono, M., Nosaka, T., Nakajima, H., Williams, D.A., Kitamura, T. J. Cell Biol. (2006) [Pubmed]
  6. Human mitotic spindle-associated protein PRC1 inhibits MgcRacGAP activity toward Cdc42 during the metaphase. Ban, R., Irino, Y., Fukami, K., Tanaka, H. J. Biol. Chem. (2004) [Pubmed]
  7. Inhibition of cyclin-dependent kinase 1 induces cytokinesis without chromosome segregation in an ECT2 and MgcRacGAP-dependent manner. Niiya, F., Xie, X., Lee, K.S., Inoue, H., Miki, T. J. Biol. Chem. (2005) [Pubmed]
  8. Phosphorylation by aurora B converts MgcRacGAP to a RhoGAP during cytokinesis. Minoshima, Y., Kawashima, T., Hirose, K., Tonozuka, Y., Kawajiri, A., Bao, Y.C., Deng, X., Tatsuka, M., Narumiya, S., May, W.S., Nosaka, T., Semba, K., Inoue, T., Satoh, T., Inagaki, M., Kitamura, T. Dev. Cell (2003) [Pubmed]
  9. Ect2 and MgcRacGAP regulate the activation and function of Cdc42 in mitosis. Oceguera-Yanez, F., Kimura, K., Yasuda, S., Higashida, C., Kitamura, T., Hiraoka, Y., Haraguchi, T., Narumiya, S. J. Cell Biol. (2005) [Pubmed]
  10. A GTPase-activating protein binds STAT3 and is required for IL-6-induced STAT3 activation and for differentiation of a leukemic cell line. Tonozuka, Y., Minoshima, Y., Bao, Y.C., Moon, Y., Tsubono, Y., Hatori, T., Nakajima, H., Nosaka, T., Kawashima, T., Kitamura, T. Blood (2004) [Pubmed]
  11. Tat1, a novel sulfate transporter specifically expressed in human male germ cells and potentially linked to rhogtpase signaling. Toure, A., Morin, L., Pineau, C., Becq, F., Dorseuil, O., Gacon, G. J. Biol. Chem. (2001) [Pubmed]
  12. Endomitotic megakaryocytes form a midzone in anaphase but have a deficiency in cleavage furrow formation. Geddis, A.E., Kaushansky, K. Cell Cycle (2006) [Pubmed]
  13. MgcRacGAP controls the assembly of the contractile ring and the initiation of cytokinesis. Zhao, W.M., Fang, G. Proc. Natl. Acad. Sci. U.S.A. (2005) [Pubmed]
  14. Aurora-B and Rho-kinase/ROCK, the two cleavage furrow kinases, independently regulate the progression of cytokinesis: possible existence of a novel cleavage furrow kinase phosphorylates ezrin/radixin/moesin (ERM). Yokoyama, T., Goto, H., Izawa, I., Mizutani, H., Inagaki, M. Genes Cells (2005) [Pubmed]
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