Src kinase and PI 3-kinase as a transduction pathway in ceramide-induced contraction of colonic smooth muscle.
Am J Physiol
; 275(4): G705-11, 1998 10.
Article
en En
| MEDLINE
| ID: mdl-9756500
ABSTRACT
Ceramide mediates sustained contraction of smooth muscle cells. C2 ceramide induced a rapid increase in Src kinase activity within 15 s, peaked at 1 min, and was sustained up to 8 min. Contraction and Src kinase activity were inhibited in cells incubated in Ca2+-free medium containing 2 mM EGTA and in cells preincubated with herbimycin A, a Src kinase inhibitor. Immunoblotting using a phosphospecific anti-Src (416Y) antibody showed a ceramide-induced increase in pp60(src) tyrosine phosphorylation. Immunoprecipitation using an anti-phosphotyrosine antibody followed by Western immunoblotting using a monoclonal IgG anti-phosphoinositide 3-kinase NH2 terminal-SH2 domain antibody showed a ceramide-induced increase in phosphoinositide 3-kinase (PI 3-kinase) tyrosine phosphorylation at a protein mass corresponding to 85 kDa, the regulatory subunit of PI 3-kinase, which contains the Src kinase binding site. PI 3-kinase phosphorylation was inhibited by herbimycin A and by the PI 3-kinase inhibitors wortmannin and LY-294002. Preincubation of cells with herbimycin A or PI 3-kinase inhibitors also resulted in an inhibition of mitogen-activated protein (MAP) kinase p42 and p44 activities as seen on Western blots. In summary, we found that 1) the maintenance of sustained contraction is dependent on extracellular Ca2+; 2) ceramide activates a nonreceptor tyrosine kinase pathway through activation of pp60(src) and PI 3-kinase; and 3) the converging signals are probably through activation of MAP kinase.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Esfingosina
/
Proteínas Tirosina Quinasas
/
Transducción de Señal
/
Colon
/
Fosfatidilinositol 3-Quinasas
/
Contracción Muscular
/
Músculo Liso
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Am J Physiol
Año:
1998
Tipo del documento:
Article
País de afiliación:
Estados Unidos