Protein kinase-A dependent phosphorylation of transcription enhancer factor-1 represses its DNA-binding activity but enhances its gene activation ability
Protein kinase-A dependent phosphorylation of transcription enhancer factor-1 represses its DNA-binding activity but enhances its gene activation ability
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DOI：
10.1093/nar/28.16.3168
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发表时间：
2000-08-15
影响因子：
14.9
通讯作者：
Gupta, M
中科院分区：
文献类型：
--
作者：
Gupta, MP;Kogut, P;Gupta, M
cAMP依赖性信号通路与心脏细胞生长/分化和肌肉基因转录有关。此前，我们在心脏α-肌球蛋白重链（α-NHC）基因启动子中鉴定了cAMP诱导的E-box/M-CAT混合基序。与该基序结合的两个因子 TEF-1 和 Max 被发现在物理上相互关联，并对基因调控发挥积极的协同作用。在这里，我们表明 TEF-1 而不是 Max 是蛋白激酶 A (PK-A) 依赖性磷酸化的底物。 TEF-1 在残基丝氨酸 102 处被 PK-A 磷酸化，TEF-1 的这种翻译后修饰抑制了其 DNA 结合活性，但不抑制其与 Max 蛋白相互作用的能力。用中性或带电氨基酸替换 TEF-1 中的丝氨酸 102 并没有消除其 DNB 结合能力，表明改变 TEF-1 102 氨基酸位置的电荷不足以抑制其 DNA 结合我们还表明，野生型 TEF-1 的存在会刺激 α-MHC 基因的 PK-A 反应，但丝氨酸 102 被丙氨酸取代的突变体 TEF-1 不会刺激 α-MHC 基因的 PK-A 反应，这表明该残基的磷酸化解释了该基因的 cAMP/PK-A 反应。因此，这些数据证明 TEF-1 是心肌细胞中 cAMP/PK-A 信号传导的直接靶标。
The cAMP-dependent signaling pathway has been implicated in cardiac cell growth/differentiation and muscle gene transcription, Previously, we have identified a cAMP-inducible E-box/M-CAT hybrid motif in the cardiac alpha-myosin heavy chain (alpha-NHC) gene promoter. The two factors, TEF-1 and Max, that bind to this motif are found to physically associate with each other and exert a positive cooperative effect for gene regulation, Here we show that TEF-1, but not Max, is a substrate for protein kinase-A (PK-A)-dependent phosphorylation. TEF-1 is phosphorylated by PK-A at residue serine-102, This post-translational modification of TEF-1 repressed its DNA-binding activity, but not its ability to interact with the Max protein, Replacement of serine-102 in TEF-1 by a neutral or a charged amino acid did not abolish its DNB-binding ability, suggesting that changing a charge at the 102 amino-acid position of TEF-1 was not sufficient to inhibit its DNA-binding activity, We also show that PK-A response of the alpha-MHC gene is stimulated by the presence of wild-type TEF-1 but not by mutant TEF-1 having serine-102 replaced by alanine, suggesting that phosphorylation at this residue accounts for the cAMP/PK-A response of the gene, Thus, these data demonstrate that TEF-1 is a direct target of cAMP/PK-A signaling in cardiac myocytes.