Structure and mutagenesis of the Dbl homology domain.
Guanine nucleotide exchange factors in the Dbl family activate Rho GTPases by accelerating dissociation of bound GDP, promoting acquisition of the GTP-bound state. Dbl proteins possess a approximately 200 residue catalytic Dbl-homology (DH) domain, that is arranged in tandem with a C-terminal pleckstrin homology (PH) domain in nearly all cases. Here we report the solution structure of the DH domain of human PAK-interacting exchange protein (betaPIX). The domain is composed of 11 alpha-helices that form a flattened, elongated bundle. The structure explains a large body of mutagenesis data, which, along with sequence comparisons, identify the GTPase interaction site as a surface formed by three conserved helices near the center of one face of the domain. Proximity of the site to the DH C-terminus suggests a means by which PH-ligand interactions may be coupled to DH-GTPase interactions to regulate signaling through the Dbl proteins in vivo.
Aghazadeh
B
B
Cellular Biochemistry and Biophysics Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
Zhu
K
K
Kubiseski
T J
TJ
Liu
G A
GA
Pawson
T
T
Zheng
Y
Y
Rosen
M K
MK
D000595:Amino Acid Sequence; D001798:Blood Proteins / Q000737:chemistry* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D020134:Catalytic Domain / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli; D016368:Frameshift Mutation; D020558:GTP Phosphohydrolases / Q000235:genetics / Q000378:metabolism*; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors; D006153:Guanosine Diphosphate / Q000378:metabolism; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010750:Phosphoproteins; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000737:chemistry* / Q000235:genetics; D064067:Rho Guanine Nucleotide Exchange Factors; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D020764:cdc42 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein
D001798:Blood Proteins; D029742:Caenorhabditis elegans Proteins; D018797:Cell Cycle Proteins; C490796:FGD1 protein, human; D020662:Guanine Nucleotide Exchange Factors; D015801:Helminth Proteins; C057811:MCF2 protein, human; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011506:Proteins; D011518:Proto-Oncogene Proteins; D064067:Rho Guanine Nucleotide Exchange Factors; C111263:UNC-73 protein, C elegans; C039077:platelet protein P47; D006153:Guanosine Diphosphate; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins; D020764:cdc42 GTP-Binding Protein; D020742:rhoA GTP-Binding Protein