Nuclear envelope precursor vesicle targeting to chromatin is stimulated by protein phosphatase 1 in Xenopus egg extracts

Journal Article · Tue May 15 04:00:00 EDT 2007 · Experimental Cell Research

DOI:https://doi.org/10.1016/j.yexcr.2007.03.015· OSTI ID:20972157

Ito, Hiromi ^[1]; Koyama, Yuhei ^[1]; Takano, Makoto ^[1]; Ishii, Kohei ^[1]; Maeno, Mitsugu ^[2]; Furukawa, Kazuhiro ^[1]; Horigome, Tsuneyoshi ^[3]

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1. Courses of Fundamental Sciences, Graduate School of Science and Technology, Niigata University, Igarashi-2, Niigata 950-2181 (Japan)
2. Courses of Life and Food Sciences, Graduate School of Science and Technology, Niigata University, Igarashi-2, Niigata 950-2181 (Japan)
3. Courses of Fundamental Sciences, Graduate School of Science and Technology, Niigata University, Igarashi-2, Niigata 950-2181 (Japan) and Department of Chemistry, Faculty of Science, Niigata University, Igarashi-2, Niigata 950-2181 (Japan) and Center for Transdisciplinary Research, Niigata University, Igarashi-2, Niigata, 950-2181 (Japan)

The mechanism underlying targeting of the nuclear membrane to chromatin at the end of mitosis was studied using an in vitro cell-free system comprising Xenopus egg membrane and cytosol fractions, and sperm chromatin. The mitotic phase membrane, which was separated from a mitotic phase extract of Xenopus eggs and could not bind to chromatin, became able to bind to chromatin on pretreatment with a synthetic phase cytosol fraction of Xenopus eggs. When the cytosol fraction was depleted of protein phosphatase 1 (PP1) with anti-Xenopus PP1{gamma}1 antibodies, this ability was lost. The addition of recombinant xPP1{gamma}1 to the PP1-depleted cytosol fraction restored the ability. These and other results suggested that dephosphorylation of mitotic phosphorylation sites on membranes by PP1 in the synthetic phase cytosol fraction promoted targeting of the membranes to chromatin. On the other hand, a fragment containing the chromatin-binding domain of lamin B receptor (LBR) but not emerin inhibited targeting of membrane vesicles. It was also shown that PP1 dephosphorylates a phosphate group(s) responsible for regulation of the binding of LBR to chromatin. A possible mechanism involving PP1 and LBR for the regulation of nuclear membrane targeting to chromatin was discussed.

• OSTI ID: 20972157
• Journal Information: Experimental Cell Research, Journal Name: Experimental Cell Research Journal Issue: 9 Vol. 313; ISSN 0014-4827; ISSN ECREAL
• Country of Publication: United States
• Language: English

Related Subjects

60 APPLIED LIFE SCIENCES
ANTIBODIES
CELL MEMBRANES
CHROMATIN
EGGS
GENE REGULATION
IN VITRO
MITOSIS
PHOSPHATES
PHOSPHORYLATION
RECEPTORS
SPERMATOZOA