title: Chemoattractant-mediated Rap1 activation requires GPCR/G proteins.
abstract: Rap1 is rapidly activated upon chemoattractant stimulation and plays an important role in cell adhesion and cytoskeletal reorganization during chemotaxis. Here, we demonstrate that G-protein coupled receptors and G-proteins are essential for chemoattractant-mediated Rap1 activation in Dictyostelium. The rapid Rap1 activation upon cAMP chemoattractant stimulation was absent in cells lacking chemoattractant cAMP receptors cAR1/cAR3 or a subunit of the heterotrimeric G-protein complex Gα2. Loss of guanylyl cyclases GCA/SGC or a cGMP-binding protein GbpC exhibited no effect on Rap1 activation kinetics. These results suggest that Rap1, a key regulator for the regulation of cytoskeletal reorganization during cell movement, is activated through the G-protein coupled receptors cAR1/cAR3 and Gα2 proteins in a way independent of the cGMP signaling pathway.
authors.affiliation: Department of Biology, College of Natural Sciences, Chosun University, Gwangju 501-759, Korea.
authors.forename: Injun
authors.initials: I
authors.lastname: Cha
authors.forename: Sung H
authors.initials: SH
authors.lastname: Lee
authors.forename: Taeck J
authors.initials: TJ
authors.lastname: Jeon
mesh_terms: D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002448:Cell Adhesion; D002465:Cell Movement; D002630:Chemotactic Factors / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism; D004023:Dictyostelium / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D007700:Kinetics; D011953:Receptors, Cyclic AMP / Q000235:genetics / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D000089804:Shelterin Complex; D015398:Signal Transduction; D034501:Telomere-Binding Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D002630:Chemotactic Factors; C503121:GCA protein, human; D044385:GTP-Binding Protein alpha Subunits; D047908:Intracellular Signaling Peptides and Proteins; D011953:Receptors, Cyclic AMP; D043562:Receptors, G-Protein-Coupled; D000089804:Shelterin Complex; C440809:TERF2IP protein, human; D034501:Telomere-Binding Proteins; C068125:cyclic AMP receptor cAR1; C022994:cyclic GMP-binding protein; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; C437313:SgcA protein, Dictyostelium discoideum; D006162:Guanylate Cyclase