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PIKE/nuclear PI 3‐kinase signaling in preventing programmed cell death
Author(s) -
Ye Keqiang
Publication year - 2005
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.20549
Subject(s) - microbiology and biotechnology , pi3k/akt/mtor pathway , nerve growth factor , protein kinase b , dna fragmentation , biology , apoptosis , programmed cell death , signal transduction , nuclear protein , nuclear export signal , nuclear transport , cell nucleus , transcription factor , receptor , nucleus , biochemistry , gene
PI 3‐kinase enhancer (PIKE) is a nuclear GTPase that enhances PI 3‐kinase (PI3K) activity. Nerve growth factor (NGF) treatment leads to PIKE activation by triggering the nuclear translocation of PLC‐γ1, which acts as a physiological guanine nucleotide exchange factor (GEF) for PIKE. PI3K occurs in the nuclei of a broad range of cell types, and various stimuli elicit PI3K nuclear translocation. While cytoplasmic PI3K has been well characterized, little is known about the biological function of nuclear PI3K. Surprisingly, nuclei from 30 min NGF‐treated PC12 cells are resistant to DNA fragmentation initiated by the activated cell‐free apoptosome, and both PIKE and nuclear PI3K are sufficient and necessary for this effect. Moreover, pretreatment of the control nucleus with PI(3,4,5)P 3 alone mimics the anti‐apoptotic activity of NGF by selectively preventing apoptosis, for which nuclear Akt is required but not sufficient. Recently, a nuclear PI(3,4,5)P 3 receptor, nucleophosmin/B23, has been identified from NGF‐treated PC12 nuclear extract. PI(3,4,5)P 3 /B23 complex mediates the anti‐apoptotic effects of NGF by inhibiting DNA fragmentation activity of caspase‐activated DNase (CAD). Thus, PI(3,4,5)P 3 /B23 complex and nuclear Akt effectors might coordinately mediate PIKE/nuclear PI3K signaling in promoting cell survival by NGF. © 2005 Wiley‐Liss, Inc.