The DH-PH region of the giant protein UNC-89 activates RHO-1 GTPase in Caenorhabditis elegans body wall muscle.
Mutation of the Caenorhabditis elegans gene unc-89 results in disorganization of muscle A-bands. unc-89 encodes a giant polypeptide (900 kDa) containing a DH domain followed by a PH domain at its N terminus, which is characteristic of guanine nucleotide exchange factor proteins for Rho GTPases. To obtain evidence that the DH-PH region has activity toward specific Rho family small GTPases, we conducted an experiment using the yeast three-hybrid system. The DH-PH region of UNC-89 has exchange activity for RHO-1 (C. elegans RhoA), but not for CED-10 (C. elegans Rac), MIG-2 (C. elegans RhoG), or CDC-42 (C. elegans Cdc42). The DH domain alone has similar activity for RHO-1. An in vitro binding assay demonstrates interaction between the DH-PH region of UNC-89 and each of the C. elegans Rho GTPases. Partial knockdown of rho-1 in C. elegans adults showed a pattern of disorganization of myosin thick filaments similar to the phenotype caused by unc-89 (su75), a mutant allele in which all of the isoforms containing the DH-PH region are missing. Taken together, we propose a model in which the DH-PH region of UNC-89 activates RHO-1 GTPase for organization of myosin filaments in C. elegans muscle cells.
Qadota
Hiroshi
H
Department of Pathology, Emory University, Atlanta, Georgia 30322, USA.
Blangy
Anne
A
Xiong
Ge
G
Benian
Guy M
GM
D000818:Animals; D017173:Caenorhabditis elegans / Q000033:anatomy & histology / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D009124:Muscle Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D009218:Myosins / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020798:Two-Hybrid System Techniques; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D007527:Isoenzymes; D009124:Muscle Proteins; D011993:Recombinant Fusion Proteins; C098932:Unc-89 protein, C elegans; D018995:Myosin Heavy Chains; D009218:Myosins; D020741:rho GTP-Binding Proteins
J Biol Chem. 1998 Mar 27;273(13):7725-30
9516480
J Cell Biol. 1996 Mar;132(5):835-48
8603916
Rev Physiol Biochem Pharmacol. 1999;138:235-68
10396143
Trends Biochem Sci. 1999 Aug;24(8):306-11
10431174
Nat Rev Mol Cell Biol. 2005 Feb;6(2):167-80
15688002
Biochem Biophys Res Commun. 2005 Sep 16;335(1):139-45
16055082
Annu Rev Cell Dev Biol. 2005;21:247-69
16212495
J Muscle Res Cell Motil. 2005;26(6-8):435-47
16453163
Development. 2006 Sep;133(18):3507-16
16899536
Mol Biol Cell. 2006 Sep;17(9):3832-47
16790495
Nat Cell Biol. 2006 Sep;8(9):978-85
16921365
Science. 2006 Sep 1;313(5791):1298-301
16873611
Mol Biol Cell. 2007 Nov;18(11):4317-26
17761533
WormBook. 2006;:1-16
18050483
Gene. 2001 Jan 24;263(1-2):103-12
11223248
FEBS Lett. 2000 Sep 1;480(2-3):287-92
11034346
Mol Biol Cell. 2008 Jun;19(6):2424-32
18337465
J Cell Biol. 2001 Jul 9;154(1):123-36
11448995
Biophys J. 2002 Jan;82(1 Pt 1):493-508
11751336
Curr Biol. 2002 Aug 6;12(15):1317-9
12176360
J Mol Biol. 2004 Sep 3;342(1):91-108
15313609
Dev Biol. 1980 Jun 15;77(2):271-302
7190524
Cell. 1983 Sep;34(2):477-90
6352051
Cell. 1993 Jul 2;73(7):1291-305
8391930
Annu Rev Cell Biol. 1994;10:31-54
7888179
Cell. 1998 Mar 20;92(6):785-95
9529254