Pim-1 associates with protein complexes necessary for mitosis

被引：98

作者：

Bhattacharya, N

Wang, ZP

Davitt, C

McKenzie, IFC

Xing, PX

Magnuson, NS ^{[1
]}

机构：

[1] Washington State Univ, Sch Mol Biosci, Pullman, WA 99164 USA

[2] Washington State Univ, Sch Biol Sci, Ctr Electron Microscopy, Pullman, WA 99164 USA

[3] Washington State Univ, Canc Prevent & Res Ctr, Pullman, WA 99164 USA

来源：

CHROMOSOMA | 2002年 / 111卷 / 02期

关键词：

D O I：

10.1007/s00412-002-0192-6

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The proto-oncogene pim-1 is a serine/threonine kinase the over-expression of which promotes lymphoma formation. Neither the normal function of Pim-1 nor the biochemical mechanism for cancer development mediated by the gene has been delineated, although recent studies have provided compelling evidence that Pim-1 is involved in differentiation and cell survival. We now provide the first evidence that Pim-1 may be involved in the proliferative process. By confocal microscopy, we observed a dynamic redistribution of Pim-1 during the cell cycle, the protein moving from the nucleus and cytoplasm in interphase to the spindle poles during mitosis. From a computer search for putative substrates of Pim-1 that are located in the spindle poles, we discovered that the nuclear mitotic apparatus (NuMA) protein has two peptide sequences that contain preferred phosphorylation sites for Pim-1 kinase. Recombinant glutathione-S-transferase-Pim-1 also readily phosphorylates immunoprecipitated NuMA. By confocal microscopy and co-immunoprecipitation we showed the interaction of the Pim-1 and NuMA proteins in HeLa cells that had been arrested during mitosis with nocodazole. Pim-1 also appeared to interact with heterochromatin-associated protein 1beta (HPIP) and the cytoplasmic proteins dynein and dynactin via. complex formation with NuMA. In our studies, overexpressed wild-type-Pim-1-GFP (green fluorescent protein) fusion protein was found to co-localize in the spindle pole with NuMA during mitosis. In contrast, the 'kinase-dead' mut-Pim-1-GFP fusion protein did not co-localize with NuMA, and appeared to promote apoptosis. Further evidence for apoptotic cell death was the observed blebbing and fragmentation of the chromosomes and a decrease in the level of NuMA protein detected by confocal microscopy. These results strongly suggest that Pim-1 kinase plays a role, most likely by phosphorylation, in promoting complex formation between NuMA, HPIP, dynein and dynactin, a complex that is necessary for mitosis.

引用

页码：80 / 95

页数：16

共 55 条

[1] Functional mammalian homologues of the Drosophila PEV-modifier Su(var)3-9 encode centromere-associated proteins which complex with the heterochromatin component M31 [J].