The cyclase-associated protein CAP as regulator of cell polarity and cAMP signaling in Dictyostelium.
Cyclase-associated protein (CAP) is an evolutionarily conserved regulator of the G-actin/F-actin ratio and, in yeast, is involved in regulating the adenylyl cyclase activity. We show that cell polarization, F-actin organization, and phototaxis are altered in a Dictyostelium CAP knockout mutant. Furthermore, in complementation assays we determined the roles of the individual domains in signaling and regulation of the actin cytoskeleton. We studied in detail the adenylyl cyclase activity and found that the mutant cells have normal levels of the aggregation phase-specific adenylyl cyclase and that receptor-mediated activation is intact. However, cAMP relay that is responsible for the generation of propagating cAMP waves that control the chemotactic aggregation of starving Dictyostelium cells was altered, and the cAMP-induced cGMP production was significantly reduced. The data suggest an interaction of CAP with adenylyl cyclase in Dictyostelium and an influence on signaling pathways directly as well as through its function as a regulatory component of the cytoskeleton.
Center for Biochemistry, Medical Faculty, University of Cologne, 50931 Cologne, Germany.
Angelika A
AA
Noegel
Rosemarie
R
Blau-Wasser
Hameeda
H
Sultana
Rolf
R
Müller
Lars
L
Israel
Michael
M
Schleicher
Hitesh
H
Patel
Cornelis J
CJ
Weijer
D000199:Actins / Q000378:metabolism; D000818:Animals; D016764:Cell Polarity / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism*; D004023:Dictyostelium / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology
D000199:Actins; D005656:Fungal Proteins; D000242:Cyclic AMP