Protein kinase C phosphorylates a recently identified membrane skeleton-associated calmodulin-binding protein in human erythrocytes.
Protein kinase C phosphorylates a recently identified membrane skeleton-associated calmodulin-binding protein in human erythrocytes.
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DOI：
10.1016/s0021-9258(18)66951-0
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发表时间：
1986-10
期刊：
影响因子：
--
通讯作者：
E. Ling;K. Gardner;V. Bennett
中科院分区：
文献类型：
--
作者：
E. Ling;K. Gardner;V. Bennett
最近，一种具有钙调素结合活性的膜骨架相关蛋白已从人红细胞中纯化并鉴定出来（Gardner， K. and Bennett， V., 1986）。化学，261,1339 -1348)。这种新蛋白（CaM-BP103/97）现在已被确定为红细胞中蛋白激酶C的主要底物，因为在以下条件下，它的两个亚基（Mr = 103,000和97,000）的磷酸化在12-O-tetradecanoylphorbol beta-acetate （TPA）存在时提高了3-15倍：用纯化自大鼠脑的蛋白激酶C孵育的鬼膜，用TPA预处理的红细胞的鬼膜，以及用32PO4代谢标记并经TPA刺激的完整红细胞的鬼膜。该蛋白被外源性和内源性蛋白激酶C磷酸化的位点是相同的，因为内源性或外源性酶标记的两个亚基的二维32p肽图是无法区分的。CaM-BP103/97的每个亚基接受高达3mol的磷酸/多肽链。在低钙浓度和没有细胞质溶胶的情况下，CaM-BP103/97的磷酸化，在摩尔基础上等于或大于蛋白4.1和4.9的磷酸化。CaM-BP103/97作为钙调素和蛋白激酶C的靶点，可能在钙对红细胞膜形状和稳定性的影响中发挥关键作用。
A membrane skeleton-associated protein with calmodulin-binding activity recently has been purified and characterized from human erythrocytes (Gardner, K. and Bennett, V. (1986) J. Biol. Chem. 261, 1339-1348). This new protein (CaM-BP103/97) has now been identified as a major substrate for protein kinase C in erythrocytes since phosphorylation of both of its subunits (Mr = 103,000 and 97,000) is elevated 3-15-fold in the presence of the phorbol ester, 12-O-tetradecanoylphorbol beta-acetate (TPA), under the following conditions: ghost membranes incubated with protein kinase C purified from rat brain, ghost membranes from erythrocytes pretreated with TPA, and intact erythrocytes metabolically labeled with 32PO4 and stimulated by TPA. The sites of phosphorylation of this protein by exogenous and endogenous protein kinase C are identical since two-dimensional 32P-peptide maps of both subunits labeled by either endogenous or exogenous enzyme are indistinguishable. Each subunit of CaM-BP103/97 accepts up to 3 mol of phosphate/polypeptide chain. In the presence of low calcium concentrations and in the absence of cytosol, the phosphorylation of CaM-BP103/97 is, on a molar basis, equal to or greater than that of proteins 4.1 and 4.9. As a target for both calmodulin and protein kinase C, CaM-BP103/97 is likely to play a key role in the effect of calcium on erythrocyte membrane shape and stability.