The β-NAD+ salvage pathway and PKC-mediated signaling influence localized PARP-1 activity and CTCF Poly(ADP)ribosylation
| Autor: | JJ L. Miranda, David J.P. Henderson, Beverly M. Emerson |
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| Rok vydání: | 2017 |
| Předmět: |
0301 basic medicine
Poly ADP ribose polymerase Context (language use) Biology Molecular biology 3. Good health Chromatin 03 medical and health sciences 030104 developmental biology 0302 clinical medicine Oncology Cell culture CTCF Cancer cell Phosphorylation 030217 neurology & neurosurgery Protein kinase C |
| Zdroj: | Oncotarget. 8:64698-64713 |
| ISSN: | 1949-2553 |
| Popis: | // David J.P. Henderson 1 , JJ L. Miranda 2 and Beverly M. Emerson 1 1 The Salk Institute for Biological Studies, La Jolla, CA, USA 2 Department of Cellular and Molecular Pharmacology , University of California, San Francisco, CA, USA Correspondence to: Beverly M. Emerson, email: // Keywords : Poly(ADP)ribosylation, CTCF, NMNAT-1, β-NAD+, PARP-1 Received : April 12, 2017 Accepted : July 06, 2017 Published : August 03, 2017 Abstract Poly(ADP)ribosylation (PARylation) of the chromatin architectural protein CTCF is critical for CTCF-dependent regulation of chromatin boundary and insulator elements. Loss of CTCF PARylation results in epigenetic silencing of certain tumor suppressor genes through destabilization of nearby chromatin boundaries. We investigated the metabolic and mechanistic processes that regulate PARP-1-mediated CTCF PARylation in human cancer cell lines and discovered a key role for the expression and activity of β-NAD+ salvage enzymes, NAMPT and NMNAT-1. These enzymes are downregulated in cells that exhibit reduced CTCF PARylation, resulting in a decreased concentration of nuclear β-NAD+. In these cells, decreased NMNAT-1 expression is enforced by a proteasome-mediated feedback loop resulting in degradation of NMNAT-1, transcriptional repression of NAMPT, and suppression of PARP-1 activity. Interestingly, dePARylated CTCF is associated in a stable protein complex with PARP-1 and NMNAT-1 in cancer cells harboring silenced tumor suppressor genes. Although the metabolic context in these cells favors suppression of PARP-1 activity, CTCF PARylation can be restored by Protein Kinase C (PKC) signaling. PKC induces dissociation of the catalytically inactive PARP-1/NMNAT-1/CTCF protein complex and phosphorylation of NMNAT-1, which stimulates its proteasome-mediated degradation. Our findings suggest that CTCF PARylation is underpinned by a cellular metabolic context engendered by regulation of the β-NAD+ salvage pathway in which NMNAT-1 acts as a rheostat to control localized β-NAD+ synthesis at CTCF/PARP-1 complexes. |
| Databáze: | OpenAIRE |
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