Localization of the G protein betagamma complex in living cells during chemotaxis.
Gradients of chemoattractants elicit signaling events at the leading edge of a cell even though chemoattractant receptors are uniformly distributed on the cell surface. In highly polarized Dictyostelium discoideum amoebas, membrane-associated betagamma subunits of heterotrimeric guanine nucleotide-binding proteins (G proteins) were localized in a shallow anterior-posterior gradient. A uniformly applied chemoattractant generated binding sites for pleckstrin homology (PH) domains on the inner surface of the membrane in a pattern similar to that of the Gbetagamma subunits. Loss of cell polarity resulted in uniform distribution of both the Gbetagamma subunits and the sensitivity of PH domain recruitment. These observations indicate that Gbetagamma subunits are not sufficiently localized to restrict signaling events to the leading edge but that their distribution may determine the relative chemotactic sensitivity of polarized cells.
Jin
T
T
Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Zhang
N
N
Long
Y
Y
Parent
C A
CA
Devreotes
P N
PN
D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D002630:Chemotactic Factors / Q000494:pharmacology; D002633:Chemotaxis / Q000502:physiology*; D000242:Cyclic AMP / Q000494:pharmacology; D004023:Dictyostelium / Q000378:metabolism / Q000502:physiology*; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D019204:GTP-Binding Proteins / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D015398:Signal Transduction
D002630:Chemotactic Factors; C118981:G-protein Beta gamma; D044387:GTP-Binding Protein beta Subunits; D044388:GTP-Binding Protein gamma Subunits; D011993:Recombinant Fusion Proteins; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D020962:Heterotrimeric GTP-Binding Proteins