Regulation of receptor capping in mouse lymphoma T cells by Ca2+-activated myosin light chain kinase.
Regulation of receptor capping in mouse lymphoma T cells by Ca2+-activated myosin light chain kinase.
复制标题
Ca2 激活的肌球蛋白轻链激酶对小鼠淋巴瘤 T 细胞受体加帽的调节。
DOI：
10.1073/pnas.81.1.165
复制
发表时间：
1984
影响因子：
11.1
通讯作者：
Bourguignon,LY
中科院分区：
文献类型：
--
作者：
Kerrick,WG;Bourguignon,LY
淋巴细胞膜上的受体帽的几个特征表明与平滑肌纤维收缩控制的潜在机制相似。加帽和收缩都是Ca 2+依赖性的，并且需要代谢能量。收缩蛋白如肌动蛋白和肌球蛋白与帽相关，钙调蛋白介导平滑肌收缩的Ca 2+依赖性。最近的研究表明，肌球蛋白轻链激酶（MLCK），这在平滑肌收缩的调节中起着核心作用，也存在于分离的淋巴细胞膜-细胞骨架复合物。我们已经进一步探索了这种类比，使用小鼠淋巴瘤T细胞，其膜通过使用类似于用于化学皮肤平滑肌细胞的低Ca 2 + EGTA溶液而被赋予对小蛋白的渗透性。然后将透化的淋巴细胞暴露于含有高或低Ca 2+、ATP或其他核苷酸的各种组合的溶液中（5 '-腺苷酰亚胺二磷酸、腺苷5'-[γ-硫代]三磷酸、鸟苷5 '-[γ-硫代]三磷酸、CTP、ITP、UTP和GTP）、钙调蛋白、Ca 2+不敏感MLCK（MLCK亚基，其已被剥离Ca 2+结合位点），和cAMP依赖性蛋白激酶的催化亚基，其磷酸化（并因此失活）MLCK。对这些各种测试溶液中伴刀豆球蛋白A标记的受体的加帽进行评分。在所有的解决方案中，在可渗透性淋巴瘤细胞中观察到的封盖与先前在类似处理的皮肤平滑肌纤维中观察到的收缩相关，为肌球蛋白轻链磷酸化参与受体封盖的调节提供了强有力的证据。
Several characteristics of receptor capping in lymphocyte membranes suggest similarities with mechanisms underlying control of contraction in smooth muscle fibers. Both capping and contraction are Ca2+ dependent and require metabolic energy. Contractile proteins such as actin and myosin are associated with the cap, as is calmodulin, which mediates the Ca2+ dependence of smooth muscle contraction. Recent studies have shown that myosin light chain kinase (MLCK), which plays a central role in regulation of smooth muscle contraction, is also present in isolated lymphocyte membrane-cytoskeleton complexes. We have explored this analogy further, using mouse lymphoma T cells whose membranes were rendered permeable to small proteins by using a low-Ca2+ EGTA solution similar to that used to chemically skin smooth muscle cells. Permeabilized lymphocytes were then exposed to solutions containing various combinations of high or low Ca2+, ATP, or other nucleotides (5'-adenylyl imidodiphosphate, adenosine 5'-[gamma-thio]triphosphate, guanosine 5'-[gamma-thio]triphosphate, CTP, ITP, UTP, and GTP), calmodulin, Ca2+-insensitive MLCK (MLCK subunit that has been stripped of the Ca2+ binding site), and the catalytic subunit of cAMP-dependent protein kinase that phosphorylates (and thereby inactivates) MLCK. Capping of concanavalin A-labeled receptors in these various test solutions was scored. In all solutions the capping observed in permeable lymphoma cells correlated well with contraction previously observed in similarly treated skinned smooth muscle fibers, providing strong evidence for the involvement of myosin light chain phosphorylation in the regulation of receptor capping.