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Induction of abnormal nuclear shapes in two distinct modes by overexpression of serine/threonine protein phosphatase 5 in Hela cells
Author(s) -
Fukuda Hirokazu,
Tsuchiya Naoto,
HaraFujita Kaori,
Takagi Sachiyo,
Nagao Minako,
Nakagama Hitoshi
Publication year - 2006
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.21178
Subject(s) - hela , serine , threonine , phosphatase , chemistry , protein phosphatase 2 , microbiology and biotechnology , protein phosphatase 1 , nuclear protein , phosphorylation , biochemistry , biology , cell , gene , transcription factor
Okadaic acid‐sensitve serine/threonine protein phosphatase 5 (PP5) is expressed ubiquitously in various tissues and is considered to participate in many cellular processes. PP5 has a catalytic domain in the C‐terminal region and three tetratricopeptide repeat (TPR) motifs in the N‐terminal region, which are suspected to function as a protein–protein interaction domain. Physiological roles of PP5 are still largely unknown, although several PP5‐binding proteins were reported and a few in vivo functions of PP5 were suggested. In the present study, the effects of expression of the full‐length wild‐type PP5 fused with EGFP (EGFP‐PP5 WT ) and its phosphatase‐dead mutant EGFP‐PP5 H304A were investigated. Transient expression of either EGFP‐PP5 WT or EGFP‐PP5 H304A in HeLa cells induced deformed nuclei with a 10‐fold frequency compared to that of EGFP. Abnormal‐shaped nuclei were also substantially increased by induced moderate expression of PP5 in tet‐on HeLa cells. Many HeLa cells expressing EGFP‐PP5 WT possessed multi‐nuclei separated from each other by nuclear membrane, while expression of EGFP‐PP5 H304A induced deformed nuclei which were multiple‐like in shape, but not separated completely and were surrounded by one nuclear membrane. These results suggest that PP5 plays important roles at the M‐phase of the cell cycle, especially in separation of chromosomes and formation of nuclear membrane. J. Cell. Biochem. 101: 321–330, 2007. © 2006 Wiley‐Liss, Inc.