INHIBITION OF ADENYLYL-CYCLASE BY G(I-ALPHA)
INHIBITION OF ADENYLYL-CYCLASE BY G(I-ALPHA)
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DOI：
10.1126/science.8327893
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发表时间：
1993-07-09
期刊：
影响因子：
56.9
通讯作者：
GILMAN, AG
中科院分区：
文献类型：
--
作者：
TAUSSIG, R;INIGUEZLLUHI, JA;GILMAN, AG
有证据表明，异三聚体鸟嘌呤核苷酸结合调节蛋白（G蛋白）的α亚基和β - γ亚基都能抑制腺苷酸环化酶。虽然I型腺苷酸环化酶可被外源性β - γ直接抑制，但G（α）对腺苷酸环化酶的抑制作用尚未在体外得到令人信服的证明。浓度依赖性抑制腺苷酸环化酶纯化的G（α）亚单位被描述。活化的G（α）有效，而G（α）无效，需要G（α）的肉豆蔻酰化。抑制作用的特点取决于腺苷酸环化酶的类型和酶的激活剂的性质。抑制腺苷酸环化酶所需的G（α）浓度大大高于通常认为与生理相关的浓度。然而，分析表明，这些浓度可能是相关的和合理的。
Evidence suggests that both alpha and betagamma subunits of heterotrimeric guanine nucleotide-binding regulatory proteins (G proteins) inhibit adenylyl cyclase. Although type I adenylyl cyclase is inhibited directly by exogenous betagamma, inhibition of adenylyl cyclase by G(ialpha) has not been convincingly demonstrated in vitro. Concentration-dependent inhibition of adenylyl cyclases by purified G(ialpha) subunits is described. Activated G(ialpha) but not G(oalpha) was effective, and myristoylation of G(ialpha) was required. The characteristics of the inhibitory effect were dependent on the type of adenylyl cyclase and the nature of the activator of the enzyme. The concentrations of G(ialpha) required to inhibit adenylyl cyclase were substantially higher than those normally thought to be relevant physiologically. However, analysis indicates that these concentrations may be relevant and reasonable.