Shaw A S, Chalupny J, Whitney J A, Hammond C, Amrein K E, Kavathas P, Sefton B M, Rose J K
Department of Pathology, Yale School of Medicine, Yale University, New Haven, Connecticut 06510.
Mol Cell Biol. 1990 May;10(5):1853-62. doi: 10.1128/mcb.10.5.1853-1862.1990.
We report that the cytoplasmic domains of the T-lymphocyte glycoproteins CD4 and CD8 alpha contain short related amino acid sequences that are involved in binding the amino-terminal domain of the intracellular tyrosine protein kinase, p56lck. Transfer of as few as six amino acid residues from the cytoplasmic domain of the CD8 alpha protein to the cytoplasmic domain of an unrelated protein conferred p56lck binding to the hybrid protein in HeLa cells. The common sequence motif shared by CD4 and CD8 alpha contains two cysteines, and mutation of either cysteine in the CD4 sequence eliminated binding of p56lck.p56lck also contains two cysteine residues within its CD4-CD8 alpha-binding domain, and both are critical to the interaction with CD4 or CD8 alpha. Because the interaction does not involve disulfide bond formation, a metal ion could stabilize the complex.
我们报告，T淋巴细胞糖蛋白CD4和CD8α的胞质结构域含有短的相关氨基酸序列，这些序列参与结合细胞内酪氨酸蛋白激酶p56lck的氨基末端结构域。将CD8α蛋白胞质结构域中少至六个氨基酸残基转移至无关蛋白的胞质结构域，可使HeLa细胞中的杂合蛋白获得p56lck结合能力。CD4和CD8α共有的序列基序包含两个半胱氨酸，CD4序列中任一半胱氨酸的突变都会消除p56lck的结合。p56lck在其CD4 - CD8α结合结构域内也含有两个半胱氨酸残基，二者对于与CD4或CD8α的相互作用均至关重要。由于这种相互作用不涉及二硫键形成，金属离子可能会稳定该复合物。
