Identification of a distinct molecular mass G alpha(h) (transglutaminase II) coupled to alpha1-adrenoceptor in mouse heart.
Our previous studies on alpha1-adrenoceptor signaling suggested that G alpha(h) family is a signal mediator in different species. To elucidate the species-specificity of G alpha(h) family in molecular mass, we used the solubilized membranes from mouse heart and the ternary complex preparations containing alpha1-agonist/receptor/G-protein. Binding of [35S]GTPgammaS and the intensity of the [alpha-32P]GTP photoaffinity labeled protein resulting from activation of the alpha1-adrenoceptor were significantly attenuated by the antagonist, phentolamine. The molecular mass of the specific GTP-binding protein was approximately 72-kDa; homologous with G alpha(h) (transglutaminase II) family. Furthermore, immunological cross-reactivity of ternary complex from mouse heart and purified G alpha(h) from rat, guinea pig, and bovine using anti-G alpha(h7) antibody showed that their molecular masses were distinctly different and approximately 72-kDa G alpha(h) from mouse heart was the lowest molecular mass. Consistent with these observations, in co-immunoprecipitation and co-immunoadsorption of the alpha1-adrenoceptor in the ternary complex preparation by anti-G alpha(h7) antibody, the G alpha(h) family protein tightly coupled to alpha1-adrenoceptor. These results demonstrate the species-specificity of G alpha(h) family in molecular mass, especially the lowest molecular mass in mouse.
Han
K J
KJ
Department of Biochemistry, College of Medicine, Chung-Ang University, Seoul, S. Korea.
Park
H
H
Yoo
S M
SM
Baek
S H
SH
Uhm
D Y
DY
Lee
H S
HS
Yun
H Y
HY
Kwon
N S
NS
Baek
K J
KJ
D000818:Animals; D002417:Cattle; D020558:GTP Phosphohydrolases / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000276:immunology / Q000378:metabolism; D006168:Guinea Pigs; D051379:Mice; D008813:Mice, Inbred ICR; D009206:Myocardium / Q000378:metabolism*; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D051381:Rats; D018340:Receptors, Adrenergic, alpha-1 / Q000276:immunology / Q000378:metabolism*; D013045:Species Specificity; D011503:Transglutaminases / Q000276:immunology / Q000302:isolation & purification* / Q000378:metabolism
D018340:Receptors, Adrenergic, alpha-1; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D020558:GTP Phosphohydrolases; D019204:GTP-Binding Proteins