DIFFERENTIAL RESPONSE OF MYOFIBRILLAR AND CYTOSKELETAL PROTEINS IN CELLS TREATED WITH PHORBOL-MYRISTATE ACETATE
DIFFERENTIAL RESPONSE OF MYOFIBRILLAR AND CYTOSKELETAL PROTEINS IN CELLS TREATED WITH PHORBOL-MYRISTATE ACETATE
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DOI：
10.1083/jcb.108.3.1079
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发表时间：
1989-03-01
影响因子：
7.8
通讯作者：
HOLTZER, H
中科院分区：
文献类型：
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作者：
LIN, ZX;ESHLEMAN, J;HOLTZER, H
肌肉特异性和非肌肉收缩性蛋白同型体对12-o-十四烷醇-13-乙酸酯（TPA）的反应方式相反。在培养第4-5天的鸡肌管中，经2 h的磷酯（TPA）处理后，发现Z带密度下降。5-10小时后，大多数I-Z-I复合物被选择性地从肌原纤维中删除，尽管A带保持完整并纵向排列。I-Z-I复合物的缺失与大量皮质α - α的出现呈负相关。-肌动蛋白含体（cab），过渡性结构。直径为M。每个CAB由一个丝状核心组成，该核心含有抗体。-肌动蛋白和肌动蛋白。每个CAB依次被一个不连续的边缘包住，这个边缘含有针对白细胞蛋白和talin的抗体。无膜cab中不含波形蛋白和聚乳酸蛋白中间丝及大部分细胞器。在接下来的10小时内，这些奇怪的小体消失了，因此在30小时的肌囊中，所有的。-肌动蛋白和肌动蛋白。-肌动蛋白结构已被消除。另一方面，即使在72小时的肌腔内，血管蛋白和talin粘连斑块仍然突出。TPA在15-20小时后（例如，15-20小时肌囊）首先开始破坏A带。长度和结构明显正常的粗细丝逐渐从A段中释放出来，到40 h，所有A带都被分解成大量随机分散但仍完整的单个粗细丝。这种分解与无定形细胞质聚集体的形成有关，这些聚集体总是与肌凝蛋白重链、MLC 1-3、肌凝蛋白和C蛋白的抗体共定位。完全消除所有免疫反应性粗丝蛋白需要60-72小时的TPA暴露。粗丝相关蛋白的消除不涉及到血管蛋白或talin的参与。与对肌原纤维的作用相反，TPA没有诱导肌囊或成纤维细胞中应激纤维和微丝中的收缩蛋白的分解。同样地，TPA在许多类型的永生化细胞中迅速诱导血管蛋白和talin易位到异位，但对肌囊、原代成纤维细胞或推定成肌细胞的粘附斑块没有明显影响。显然，收缩蛋白和一些细胞骨架同种异构体对TPA的反应不仅因表型而异，而且即使在给定的肌管结构域内，肌原纤维也以一种方式反应，应激纤维/微丝则以另一种方式反应。
Muscle-specific and nonmuscle contractile protein isoforms responded in opposite ways to 12-o-tetradecanoyl phorbol-13-acetate (TPA). Loss of Z band density was observed in day 4-5 cultured chick myotubes after 2 h in the phorbol ester, TPA. By 5-10 h, most I-Z-I complexes were selectively deleted from the myofibril, although the A bands remained intact and longitudinally aligned. The deletion of I-Z-I complexes was inversely related to the appearance of numerous cortical, .alpha.-actinin containing bodies (CABs), transitory structures .apprx.3.0 .mu.m in diameter. Each CAB consisted of a filamentous core that costained with antibodies to .alpha.-actin and sarcomeric .alpha.-actinin. In turn each CAB was encaged by a discontinuous rim that constained with antibodies to vinculin and talin. Vimentin and desmin intermediate filaments and most cell organelles were excluded from the membrane-free CABs. These curious bodies disappeared over the next 10 h so that in 30-h myosacs all .alpha.-actin and sarcomeric .alpha.-actinin structures had been eliminated. On the other hand vinculin and talin adhesion plaques remained prominent even in 72-h myosacs. Disruption of the A bands was first initiated after 15-20 h in TPA (e.g., 15-20-h myosacs). Thick filaments of apparently normal length and structure were progressively released from A segments, a and by 40 h all A bands had been broken down into enormous numbers of randomly dispersed, but still intact single thick filaments. This breakdown correlated with the formation of amorphous cytoplasmic aggregates which invariably colocalized antibodies to myosin heavy chain, MLC 1-3, myomesin, and C protein. Complete elimination of all immunoreactive thick filament proteins required 60-72 h of TPA exposure. The elimination of the thick filament-associated proteins did not involve the participation of vinculin or talin. In contrast to is effects on myofibrils, TPA did not induce the disassembly of the contractile proteins in stress fibers and microfilaments either in myosacs or in fibroblastc cells. Similarly, TPA, which rapidly induces the translocation of vinculin and talin to ectopic sites in many types of immortalized cells, had no gross effect on the adhesion plaques of myosacs, primary fibroblastic cells, or presumptive myoblasts. Clearly, the response to TPA of contractile protein and some cytoskeletal isoforms not only varies among phenotypes, but even within the domains of a given myotube the myofibrils respond one way, the stress fibers/microfilaments another.