Tögel M, Eichinger R, Wiche G, Propst F
Institute of Biochemistry and Molecular Cell Biology, Vienna Biocenter, University of Vienna, Austria.
FEBS Lett. 1999 May 14;451(1):15-8. doi: 10.1016/s0014-5793(99)00523-2.
The microtubule-associated proteins 1B and 1A are synthesized as polyprotein precursors which are rapidly cleaved to give rise to heavy and light chains constituting the respective microtubule-associated protein 1B or microtubule-associated protein 1A complex. To identify domains necessary for precursor processing, we expressed microtubule-associated protein 1B deletion mutants in fibroblasts and monitored proteolytic cleavage of the precursor proteins by immunoblot analysis. We found that a novel hydrophilic, proline-rich 45 amino acid domain containing the cleavage site is necessary and sufficient for processing. This domain is conserved in microtubule-associated protein 1A. Additional sequences in the N-terminal half of the heavy chain contribute to the efficiency of cleavage.
微管相关蛋白1B和1A最初作为多蛋白前体合成，随后迅速裂解产生重链和轻链，它们共同构成了各自的微管相关蛋白1B或微管相关蛋白1A复合体。为了鉴定前体加工所需的结构域，我们在成纤维细胞中表达了微管相关蛋白1B缺失突变体，并通过免疫印迹分析监测前体蛋白的蛋白水解裂解过程。我们发现，一个含有裂解位点的新型亲水性、富含脯氨酸的45个氨基酸的结构域对于加工是必需且足够的。该结构域在微管相关蛋白1A中保守。重链N端一半的其他序列有助于提高裂解效率。
