Activation of a pertussis-toxin-sensitive guanine-nucleotide-binding regulatory protein during desensitization of Dictyostelium discoideum cells to chemotactic signals.
Activation of a pertussis-toxin-sensitive guanine-nucleotide-binding regulatory protein during desensitization of Dictyostelium discoideum cells to chemotactic signals.
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盘基网柄菌细胞对趋化信号脱敏期间百日咳毒素敏感鸟嘌呤核苷酸结合调节蛋白的激活。
DOI：
10.1111/j.1432-1033.1991.tb15758.x
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
P. V. Haastert
中科院分区：
文献类型：
--
作者：
B. Snaar;Saskia Es;F. Kesbeke;P. V. Haastert
趋化剂 cAMP 诱导盘基网柄菌中腺苷酸环化酶的激活。与 cAMP 长时间孵育后，细胞通过两个不同的过程变得脱敏：可用的 cAMP 结合位点数量减少（下调）和与适应相关的受体修饰（可能通过磷酸化）。这些过程同时发生，但 cAMP 剂量依赖性和可逆性不同。在这项研究中，我们研究了适应机制；将细胞与 cAMP 类似物一起孵育，以诱导适应介导的脱敏作用。然后洗涤、裂解细胞，并研究 cAMP、受体、鸟嘌呤核苷酸结合调节蛋白（G 蛋白）和 GTP 之间的相互作用。 (1) 体内磷酸化的 cAMP 受体在裂解后至少保持磷酸化状态 45 分钟。 (2) 脱敏不会改变基础 cAMP 与受体的结合，也不会改变鸟苷 5'-γ-硫代]三磷酸 (GTP[S]) 对这种结合的抑制作用。 (3)cAMP对GTP[S]结合的刺激作用也没有改变，而基础GTP[S]结合和结合动力学仅略有不同。 (4) 基础高亲和力 GTP 酶活性没有改变，但 cAMP 刺激从对照裂解物中的 43 +/- 7% 减少到脱敏细胞裂解物中的 14 +/- 4%。 (5)用百日咳毒素预处理细胞，GTP酶的cAMP刺激从43+/-7%减少到17+/-8%，但是在脱敏百日咳毒素处理的细胞的裂解物中这没有进一步改变。这些观察结果表明，在脱敏过程中，磷酸化受体仍然可以与 G 蛋白相互作用。此外，脱敏不会影响 GTP[S] 结合的 cAMP 刺激，但会强烈降低 GTP 酶的 cAMP 刺激，表明 G 蛋白被激活。该 G 蛋白对百日咳毒素敏感，可能是抑制剂 G 蛋白 (Gi)。这意味着腺苷酸环化酶由于 Gi 被激活而脱敏。
The chemoattractant cAMP induces the activation of adenylate cyclase in Dictyostelium discoideum. Upon prolonged incubation with cAMP, cells become desensitized via two distinct processes: a decrease in the number of available cAMP-binding sites (down regulation) and modification of the receptor (presumably via phosphorylation) correlated with adaptation. These processes occur simultaneously, but differ in the cAMP dose dependency and reversibility. In this study we investigated the mechanism of adaptation; cells were incubated with a cAMP analog to induce desensitization mediated by adaptation. The cells were then washed, lysed and the interaction between cAMP, receptor, guanine-nucleotide-binding regulatory proteins (G proteins) and GTP was investigated. (1) cAMP receptors that are phosphorylated in vivo remain phosphorylated for at least 45 min after lysis. (2) Desensitization did not alter basal cAMP binding to the receptor nor the inhibitory effect of guanosine 5'-[gamma-thio]triphosphate (GTP[S]) on this binding. (3) The stimulatory effect of cAMP on GTP[S] binding was also unchanged, while basal GTP[S] binding and the kinetics of binding were only slightly different. (4) Basal high-affinity GTPase activity was not altered but cAMP stimulation was reduced from 43 +/- 7% in control lysates to 14 +/- 4% in lysates from desensitized cells. (5) cAMP stimulation of GTPase was decreased by pretreatment of cells with pertussis toxin from 43 +/- 7% to 17 +/- 8% but this was not further altered in lysates from desensitized pertussis-toxin-treated cells. These observations indicate that during desensitization the phosphorylated receptor can still interact with G proteins. Furthermore, desensitization did not affect cAMP stimulation of GTP[S] binding but strongly reduced cAMP stimulation of GTPase, suggesting that a G protein becomes activated. This G protein is pertussis toxin sensitive and may be the inhibitor G protein (Gi). This would imply that adenylate cyclase desensitizes because Gi becomes activated.
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盘基网柄菌中环 AMP 受体的鉴定和环 AMP 诱导的修饰。
DOI：
--
发表时间：
1985
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Klein,P;Theibert,A;Fontana,D;Devreotes,PN
通讯作者：
Devreotes,PN
影响因子：
56.9
作者：
KLEIN, PS;SUN, TJ;DEVREOTES, PN
通讯作者：
DEVREOTES, PN
DOI：
--
发表时间：
1987
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Klein,P;Vaughan,R;Borleis,J;Devreotes,P
通讯作者：
Devreotes,P
盘基网柄菌膜中的百日咳和霍乱毒素 ADP-核糖基化。
DOI：
10.1016/0006-291x(87)90504-3
发表时间：
1987
影响因子：
3.1
作者：
Khachatrian,L;Klein,C;Howlett,A
通讯作者：
Howlett,A
配体诱导的盘基网柄菌 cAMP 受体磷酸化。
DOI：
--
发表时间：
1988
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Vaughan,RA;Devreotes,PN
通讯作者：
Devreotes,PN