Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 2011 Feb 8;108(6):2205-9. doi: 10.1073/pnas.1019381108. Epub 2011 Jan 24.

Casein kinase-2 mediates cell survival through phosphorylation and degradation of inositol hexakisphosphate kinase-2.

Author information

  • 1The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.

Abstract

The inositol pyrophosphate, diphosphoinositol pentakisphosphate, regulates p53 and protein kinase Akt signaling, and its aberrant increase in cells has been implicated in apoptosis and insulin resistance. Inositol hexakisphosphate kinase-2 (IP6K2), one of the major inositol pyrophosphate synthesizing enzymes, mediates p53-linked apoptotic cell death. Casein kinase-2 (CK2) promotes cell survival and is upregulated in tumors. We show that CK2 mediated cell survival involves IP6K2 destabilization. CK2 physiologically phosphorylates IP6K2 at amino acid residues S347 and S356 contained within a PEST sequence, a consensus site for ubiquitination. HCT116 cells depleted of IP6K2 are resistant to cell death elicited by CK2 inhibitors. CK2 phosphorylation at the degradation motif of IP6K2 enhances its ubiquitination and subsequent degradation. IP6K2 mutants at the CK2 sites that are resistant to CK2 phosphorylation are metabolically stable.

PMID:
21262846
[PubMed - indexed for MEDLINE]
PMCID:
PMC3038742
Free PMC Article

Images from this publication.See all images (4)Free text

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk