Pabion M, Job D, Margolis R L
Biochemistry. 1984 Dec 18;23(26):6642-8. doi: 10.1021/bi00321a055.
Microtubules are stabilized against cold temperature disassembly by 145-kilodalton proteins [stable tubule only polypeptides (STOPs)] that block the end-wise dissociation of subunits from the polymers. We describe here several kinetic parameters of the interaction of STOPs with microtubules. STOPs will bind to microtubules either during assembly of the polymer or at steady state. The addition appears random on the polymers and does not require the mediation of tubulin subunits. Tubulin subunits compete with microtubules for STOP binding, but binding to the polymers is apparently irreversible. We demonstrate that STOPs do not exchange measurably between polymers at steady state. Nonetheless, a displacement of STOPs within a single polymer is readily demonstrable. We have determined that the displacement is apparently due to a surface translocation, or "sliding", of STOPs on microtubules.
微管可通过145千道尔顿的蛋白质[仅稳定微管多肽（STOPs）]来稳定，防止其在低温下解聚，这些蛋白质可阻止亚基从聚合物上向末端解离。我们在此描述了STOPs与微管相互作用的几个动力学参数。STOPs可在聚合物组装过程中或稳态时与微管结合。这种结合在聚合物上似乎是随机的，且不需要微管蛋白亚基的介导。微管蛋白亚基与微管竞争STOPs的结合，但与聚合物的结合显然是不可逆的。我们证明，在稳态下，STOPs在聚合物之间不会发生可测量的交换。尽管如此，单个聚合物内STOPs的位移很容易得到证实。我们已经确定，这种位移显然是由于STOPs在微管上的表面易位或“滑动”所致。
