Novel phosphatidylinositol phosphate kinases with a G-protein coupled receptor signature are shared by Dictyostelium and Phytophthora.
G-protein coupled receptors (GPCR) and phosphatidylinositol phosphate kinases (PIPK) are important key switches in signal transduction pathways. A novel class of proteins was identified in the genomes of two unrelated organisms that harbor both a GPCR and a PIPK domain. Dictyostelium discoideum contains one GPCR-PIPK, which is crucial in cell-density sensing, and the genomes of Phytophthora sojae and Phytophthora ramorum each encode twelve GPCR-PIPKs. Intriguingly, these are currently the only species that have these two domains combined in one protein. Here, the structural and regulatory characteristics of GPCR-PIPKs are presented and discussed. It is hypothesized that, upon activation, GPCR-PIPKs are able to trigger heterotrimeric G-protein signaling and phosphoinositide second-messenger synthesis.
Bakthavatsalam
Deenadayalan
D
Centre for Biochemistry, Institute of Biochemistry I, Medical Faculty and Centre for Molecular Medicine Cologne, University of Cologne, D-50931 Cologne, Germany. deen@rice.edu
Meijer
Harold J G
HJ
Noegel
Angelika A
AA
Govers
Francine
F
D000595:Amino Acid Sequence; D000818:Animals; D004023:Dictyostelium / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D010838:Phytophthora / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015398:Signal Transduction
D043562:Receptors, G-Protein-Coupled; D017853:Phosphotransferases (Alcohol Group Acceptor); C020077:1-phosphatidylinositol-4-phosphate 5-kinase; D019204:GTP-Binding Proteins