PARG1, a protein-tyrosine phosphatase-associated RhoGAP, as a putative Rap2 effector.

Rap2 belongs to the Ras family of small GTP-binding proteins, but its specific signaling role is unclear. By yeast two-hybrid screening, we have found that the Caenorhabditis elegans ortholog of Rap2 interacts with a protein containing a Rho-GTPase-activating protein (RhoGAP) domain, ZK669.1a, whose human ortholog PARG1 exhibits RhoGAP activity in vitro. ZK669.1a and PARG1 share a homology region with previously unknown function, designated the ZK669.1a and PARG1 homology (ZPH) region. Here we show that the ZPH region of PARG1 mediates interaction with Rap2. PARG1 interacted with Rap2 in a GTP-dependent manner but not with Ras or Rap1. We also show that PARG1 and its mutant lacking the ZPH region induce typical cytoskeletal changes for Rho inactivation in fibroblasts. Rap2 suppressed this in vivo action of PARG1 but not that of the mutant PARG1. These results suggest that PARG1 is a putative specific effector of Rap2 to regulate Rho.

[1]  R. Wolthuis,et al.  Identification and Characterization of Potential Effector Molecules of the Ras-related GTPase Rap2* , 1999, The Journal of Biological Chemistry.

[2]  M. Gold,et al.  Activation of the Rap GTPases in B Lymphocytes Modulates B Cell Antigen Receptor-induced Activation of Akt but Has No Effect on MAPK Activation* , 2003, Journal of Biological Chemistry.

[3]  L. Buday,et al.  The Nck family of adapter proteins: regulators of actin cytoskeleton. , 2002, Cellular signalling.

[4]  K. Kariya,et al.  Mitogen-activated Protein Kinase Kinase Kinase Kinase 4 as a Putative Effector of Rap2 to Activate the c-Jun N-terminal Kinase* , 2004, Journal of Biological Chemistry.

[5]  T. Kataoka,et al.  Regulation of a Novel Human Phospholipase C, PLCε, through Membrane Targeting by Ras* , 2001, The Journal of Biological Chemistry.

[6]  S. Feller.  Crk family adaptors–signalling complex formation and biological roles , 2001, Oncogene.

[7]  E. Rubin,et al.  Functional modification of a 21-kilodalton G protein when ADP-ribosylated by exoenzyme C3 of Clostridium botulinum. , 1988, Molecular and cellular biology.

[8]  T. Kataoka,et al.  Role of Raf-1 conserved region 2 in regulation of Ras-dependent Raf-1 activation. , 2000, Biochemical and biophysical research communications.

[9]  D. Payan,et al.  TNIK, a Novel Member of the Germinal Center Kinase Family That Activates the c-Jun N-terminal Kinase Pathway and Regulates the Cytoskeleton* , 1999, The Journal of Biological Chemistry.

[10]  T. Kataoka,et al.  RA-GEF, a Novel Rap1A Guanine Nucleotide Exchange Factor Containing a Ras/Rap1A-associating Domain, Is Conserved between Nematode and Humans* , 1999, The Journal of Biological Chemistry.

[11]  I. Macara,et al.  The Function of the p190 Rho GTPase-activating Protein Is Controlled by Its N-terminal GTP Binding Domain* , 1998, The Journal of Biological Chemistry.

[12]  T Watanabe,et al.  Bni1p implicated in cytoskeletal control is a putative target of Rho1p small GTP binding protein in Saccharomyces cerevisiae. , 1996, The EMBO journal.

[13]  K. Kaibuchi,et al.  Small GTP-binding proteins. , 1992, International review of cytology.

[14]  T. Kataoka,et al.  Identification of PLC210, a Caenorhabditis elegansPhospholipase C, as a Putative Effector of Ras* , 1998, The Journal of Biological Chemistry.

[15]  Y. Matsuura,et al.  Association of Frabin with the Actin Cytoskeleton Is Essential for Microspike Formation through Activation of Cdc42 Small G Protein* , 1999, The Journal of Biological Chemistry.

[16]  U. Hellman,et al.  A Novel GTPase-activating Protein for Rho Interacts with a PDZ Domain of the Protein-tyrosine Phosphatase PTPL1* , 1997, The Journal of Biological Chemistry.

[17]  P. McPherson,et al.  The Activity of the GTPase-activating Protein CdGAP Is Regulated by the Endocytic Protein Intersectin* , 2002, The Journal of Biological Chemistry.

[18]  M. Matsuda,et al.  Rap2 as a Slowly Responding Molecular Switch in the Rap1 Signaling Cascade , 2000, Molecular and Cellular Biology.

[19]  T. Sasaki,et al.  Regulation of morphology by rho p21 and its inhibitory GDP/GTP exchange protein (rho GDI) in Swiss 3T3 cells. , 1993, The Journal of biological chemistry.

[20]  K. Kariya,et al.  The Traf2- and Nck-interacting Kinase as a Putative Effector of Rap2 to Regulate Actin Cytoskeleton* , 2004, Journal of Biological Chemistry.

[21]  T. Kataoka,et al.  Identification and Characterization of RA-GEF-2, a Rap Guanine Nucleotide Exchange Factor That Serves as a Downstream Target of M-Ras* , 2001, The Journal of Biological Chemistry.

[22]  P. Sternberg,et al.  Phospholipase Cɛ regulates ovulation in Caenorhabditis elegans , 2004 .