A cytoskeletal localizing domain in the cyclase-associated protein, CAP/Srv2p, regulates access to a distant SH3-binding site.
J Biol Chem
; 274(28): 19985-91, 1999 Jul 09.
Article
en En
| MEDLINE
| ID: mdl-10391948
ABSTRACT
In the yeast, Saccharomyces cerevisiae, adenylyl cyclase consists of a 200-kDa catalytic subunit (CYR1) and a 70-kDa subunit (CAP/SRV2). CAP/Srv2p assists the small G protein Ras to activate adenylyl cyclase. CAP also regulates the cytoskeleton through an actin sequestering activity and is directed to cortical actin patches by a proline-rich SH3-binding site (P2). In this report we analyze the role of the actin cytoskeleton in Ras/cAMP signaling. Two alleles of CAP, L16P(Srv2) and R19T (SupC), first isolated in genetic screens for mutants that attenuate cAMP levels, reduced adenylyl cyclase binding, and cortical actin patch localization. A third mutation, L27F, also failed to localize but showed no loss of either cAMP signaling or adenylyl cyclase binding. However, all three N-terminal mutations reduced CAP-CAP multimer formation and SH3 domain binding, although the SH3-binding site is about 350 amino acids away. Finally, disruption of the actin cytoskeleton with latrunculin-A did not affect the cAMP phenotypes of the hyperactive Ras2(Val19) allele. These data identify a novel region of CAP that controls access to the SH3-binding site and demonstrate that cytoskeletal localization of CAP or an intact cytoskeleton per se is not necessary for cAMP signaling.
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Colección:
01-internacional
Asunto principal:
Citoesqueleto
/
Proteínas Fúngicas
/
Adenilil Ciclasas
/
Proteínas de Ciclo Celular
/
Proteínas del Citoesqueleto
/
Proteínas de Saccharomyces cerevisiae
/
Proteínas de Drosophila
/
Proteínas de Microfilamentos
Tipo de estudio:
Risk_factors_studies
Idioma:
En
Revista:
J Biol Chem
Año:
1999
Tipo del documento:
Article
País de afiliación:
Estados Unidos