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Identification of PSF as a protein kinase Cα‐binding protein in the cell nucleus
Author(s) -
Rosenberger Uwe,
Lehmann Ingo,
Weise Christoph,
Franke Peter,
Hucho Ferdinand,
Buchner Klaus
Publication year - 2002
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.10233
Subject(s) - nucleus , identification (biology) , chemistry , microbiology and biotechnology , protein kinase a , cell , kinase , biology , biochemistry , botany
Protein kinase C (PKC) isoforms are present in the cell nucleus in diverse cell lines and tissues. Since little is known about proteins interacting with PKC inside the cell nucleus, we used Neuro‐2a neuroblastoma cells, in which PKCα is present in the nucleus, to screen for nuclear binding partners for PKC. Applying overlay assays, we detected several nuclear proteins which bind to PKCα. Specificity of binding was shown by its dependence on PKC activation by phorbol ester, calcium, and phosphatidylserine. The PKC‐binding proteins were partially purified and analyzed by microsequencing and mass spectrometry. Four proteins could be identified: PTB‐associated splicing factor (PSF), p68 RNA helicase, and the heterogeneous nuclear ribonucleoprotein (hnRNP) proteins A3 and L. In the case of PSF, binding to PKC could also be demonstrated in a GST‐pull‐down assay using GST‐PKCα, expressed in insect cells. Phosphorylation experiments revealed that PSF is a weak in vitro substrate for PKCα. J. Cell. Biochem. 86: 394–402, 2002. © 2002 Wiley‐Liss, Inc.