A spatiotemporally coordinated cascade of protein kinase C activation controls isoform-selective translocation
A spatiotemporally coordinated cascade of protein kinase C activation controls isoform-selective translocation
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DOI：
10.1128/mcb.26.6.2247-2261.2006
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发表时间：
2006-03-01
影响因子：
5.3
通讯作者：
Joubert, D
中科院分区：
文献类型：
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作者：
Collazos, A;Diouf, B;Joubert, D
在垂体 GH3B6 细胞中，涉及蛋白激酶 C (PKC) 多基因家族的信号传导可以自组织成同种型激活的时空协调级联。事实上，促甲状腺素释放激素 (TRH) 受体激活会依次激活绿色荧光蛋白 (GFP) 标记或内源性 PKC β 1、PKC α、PKC ε 和 PKC δ，导致它们在整个质膜（PKC β 和 -δ）处积累，或选择性地在细胞与细胞接触处（PKC α 和 -ε）处积累。激活的持续时间范围从 PKC α 的 20 秒到 PKC epsilon 的 20 分钟。 Go6976 存在时，PKC epsilon 和 -E 选择性定位丢失，表明细胞-细胞接触处的积累依赖于常规 PKC 的活性。组成型活性、显性失活的 PKC 和小干扰 RNA 表明 PKC α 定位受 PKC β 1 活性控制，且与钙无关，而 PKC epsilon 定位依赖于 PKCa 活性。 PKC delta 独立于连接 PKC beta 1、-alpha 和 -epsilon 的级联。此外，PKCa.（而不是 PKC epsilon）参与 TRH 诱导的细胞-细胞接触处的 β-连环蛋白重定位，表明 PKC epsilon 不是级联的唯一功能效应器。因此，TRH 受体激活导致 PKC beta 1 激活，进而启动 PKC(x 和 -E) 的钙独立但 PKC beta 1 活性依赖性顺序易位。这些结果挑战了当前对 PKC 信号传导的理解，并提出了同种型之间功能依赖性的问题。
In pituitary GH3B6 cells, signaling involving the protein kinase C (PKC) multigene family can self-organize into a spatiotemporally coordinated cascade of isoform activation. Indeed, thyrotropin-releasing hormone (TRH) receptor activation sequentially activated green fluorescent protein (GFP)-tagged or endogenous PKC beta 1, PKC alpha, PKC epsilon, and PKC delta, resulting in their accumulation at the entire plasma membrane (PKC beta and -delta) or selectively at the cell-cell contacts (PKC alpha and -epsilon). The duration of activation ranged from 20 s for PKC alpha to 20 min for PKC epsilon. PKC epsilon and -E selective localization was lost in the presence of Go6976, suggesting that accumulation at cell-cell contacts is dependent on the activity of a conventional PKC. Constitutively active, dominant-negative PKCs and small interfering RNAs showed that PKC alpha localization is controlled by PKC beta 1 activity and is calcium independent, while PKC epsilon localization is dependent on PKCa activity. PKC delta was independent of the cascade linking PKC beta 1, -alpha, and -epsilon. Furthermore, PKCa., but not PKC epsilon, is involved in the TRH-induced beta-catenin relocation at cell-cell contacts, suggesting that PKC epsilon is not the unique functional effector of the cascade. Thus, TRH receptor activation results in PKC beta 1 activation, which in turn initiates a calcium-independent but PKC beta 1 activity-dependent sequential translocation of PKC(x and -E. These results challenge the current understanding of PKC signaling and raise the question of a functional dependence between isoforms.