Identification of four phosphorylation sites in the N-terminal region of tyrosine hydroxylase.
Identification of four phosphorylation sites in the N-terminal region of tyrosine hydroxylase.
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DOI：
10.1016/s0021-9258(18)67410-1
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发表时间：
1986-08
期刊：
影响因子：
--
通讯作者：
D. Campbell;D. Hardie;P. Vulliet
中科院分区：
文献类型：
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作者：
D. Campbell;D. Hardie;P. Vulliet
如前所述[Vulliet et al.(1985)FEBS Lett.182 335-339]，从大鼠嗜铬细胞瘤中提纯的酪氨酸羟基酶被依赖于环磷酸腺苷的蛋白激酶、依赖钙调素的多蛋白激酶和蛋白激酶C在相同的位点(A位点)磷酸化，而依赖钙调素的多蛋白激酶也磷酸化另一个独特的位点(C位点)。从这个来源提纯的酪氨酸羟基酶制剂也被另一个独特的位点(E位点)磷酸化的第四个蛋白激酶的痕迹所污染。我们已经分离出了含有这些位点的胰蛋白酶多肽，并测定了它们的氨基酸序列。通过将这些数据与已知的大鼠酪氨酸羟化酶的cDNA序列进行比较，我们已经能够将这些位点鉴定为Ser-8(E位)、Ser-19(C位)和Ser-40(A位)。在一些酪氨酸羟解酶制剂中，环AMP依赖的蛋白激酶还使一个被鉴定为Ser-153的第二位点磷酸化。所有这些磷酸化位点都在氨基末端，在那里与密切相关的酶苯丙氨酸羟基酶没有显著的同源性。我们的数据还证实，启动子蛋氨酸被翻译后处理移除，留下PRO-2作为成熟蛋白的氨基末端。讨论了这些结果对于细胞外信号对儿茶酚胺生物合成的作用机制的意义。
As reported previously [Vulliet et al. (1985) FEBS Lett. 182 335-339], tyrosine hydroxylase purified from rat pheochromocytoma is phosphorylated at an identical site (site A) by cyclic AMP-dependent protein kinase, the calmodulin-dependent multiprotein kinase and protein kinase C, while the calmodulin-dependent multiprotein kinase also phosphorylates another unique site (site C). Preparations of tyrosine hydroxylase purified from this source are also contaminated with traces of a fourth protein kinase which phosphorylates another unique site (site E). We have isolated tryptic peptides containing each of these sites and determined their amino acid sequences. By comparison of these data with the known cDNA sequence for rat tyrosine hydroxylase, we have been able to identify these sites as Ser-8 (site E), Ser-19 (site C), and Ser-40 (site A). In some preparations of tyrosine hydroxlyase, cyclic AMP-dependent protein kinase also phosphorylated a secondary site which was identified as ser-153. All of these phosphorylation sites are in the amino-terminal region, where there is no significant homology with the closely related enzyme, phenylalanine hydroxylase. Our data also establish that the initiator methionine is removed by post-translational processing to leave pro-2 as the amino-terminus of the mature protein. The significance of these results for the mechanism of action of extracellular signals on catecholamine biosynthesis is discussed.