Ainsztein A M, Kandels-Lewis S E, Mackay A M, Earnshaw W C
Institute of Cell and Molecular Biology, University of Edinburgh, Edinburgh EH9 3JR, Scotland, United Kingdom.
J Cell Biol. 1998 Dec 28;143(7):1763-74. doi: 10.1083/jcb.143.7.1763.
The inner centromere protein (INCENP) has a modular organization, with domains required for chromosomal and cytoskeletal functions concentrated near the amino and carboxyl termini, respectively. In this study we have identified an autonomous centromere- and midbody-targeting module in the amino-terminal 68 amino acids of INCENP. Within this module, we have identified two evolutionarily conserved amino acid sequence motifs: a 13-amino acid motif that is required for targeting to centromeres and transfer to the spindle, and an 11-amino acid motif that is required for transfer to the spindle by molecules that have targeted previously to the centromere. To begin to understand the mechanisms of INCENP function in mitosis, we have performed a yeast two-hybrid screen for interacting proteins. These and subsequent in vitro binding experiments identify a physical interaction between INCENP and heterochromatin protein HP1(Hsalpha). Surprisingly, this interaction does not appear to be involved in targeting INCENP to the centromeric heterochromatin, but may instead have a role in its transfer from the chromosomes to the anaphase spindle.
着丝粒内部蛋白（INCENP）具有模块化结构，其染色体功能和细胞骨架功能所需的结构域分别集中在氨基末端和羧基末端附近。在本研究中，我们在INCENP氨基末端的68个氨基酸中鉴定出一个自主的着丝粒和中体靶向模块。在这个模块中，我们鉴定出两个进化上保守的氨基酸序列基序：一个13个氨基酸的基序，它是靶向着丝粒并转移到纺锤体所必需的；另一个11个氨基酸的基序，它是已靶向着丝粒的分子转移到纺锤体所必需的。为了开始理解INCENP在有丝分裂中的功能机制，我们进行了酵母双杂交筛选以寻找相互作用蛋白。这些以及随后的体外结合实验确定了INCENP与异染色质蛋白HP1（Hsalpha）之间的物理相互作用。令人惊讶的是，这种相互作用似乎并不参与将INCENP靶向着丝粒异染色质，而是可能在其从染色体转移到后期纺锤体中发挥作用。
