Regulation of Microtubule Organization during Interphase and M Phase

Cell Structure and Function

Shoichiro Tsukita¹  Nobuyuki Shiina¹ 

[1] Tsukita Cell Axis Project, ERATO, Japan Science and Technology Corporation, Kyoto Research Park, Shimogyo-ku, Kyoto 600-8813, Japan

关键词: XMAP4;    p34cdc2 kinase;    microtubule dynamics;    mitosis;    chromosome movement;    tubulin;   

DOI  :  10.1247/csf.24.385

学科分类：分子生物学，细胞生物学和基因

来源: Japan Society for Cell Biology

【 摘 要 】

References(32)Cited-By(5)Microtubule (MT) dynamics and organization change markedly during interphase-M phase transition of the cell cycle. This mini review focuses first on p220, a ubiquitous MT-associated protein of Xenopus. p220 is phosphorylated by p34cdc2 kinase and MAP kinase in M phase, and concomitantly loses its MT-binding and MT-stabilizing activities. A cDNA encoding p220 was cloned, which identified p220 as a Xenopus homolog of MAP4, and p220 was therefore termed XMAP4. To examine the physiological relevance of XMAP4 phosphorylation during mitosis, Xenopus A6 cells were transfected with cDNA encoding wild-type or various XMAP4 mutants fused with a green fluorescent protein (GFP). Mutations of serine and threonine within potential phosphorylation sites for p34cdc2 kinase to nonphosphorylatable alanine interfered with mitosis-associated reduction in MT-affinity of XMAP4 and their overexpression affected chromosome movement during anaphase A. These results indicated that phosphorylation of XMAP4 by p34cdc2 kinase is responsible for the decrease in its MT-binding and MT-stabilizing activities during mitosis which are important for chromosome movement during anaphase A. The second focus is on a novel monoclonal antibody W8C3, which recognizes α-tubulin. W8C3 stained spindle MTs but not interphase MTs of Xenopus A6 cells, although tubulin dimers in M phase and interphase were equally recognized by this antibody. The difference in MT staining pattern may be because the W8C3-recognition site on α-tubulin is sterically hidden in interphase MTs but not in spindle MTs.

【 授权许可】

Unknown