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Critical role for hyperpolarization‐activated cyclic nucleotide‐gated channel 2 in the AIF‐mediated apoptosis
Author(s) -
Norberg Erik,
Karlsson Marie,
Korenovska Olga,
Szydlowski Susanne,
Silberberg Gilad,
Uhlén Per,
Orrenius Sten,
Zhivotovsky Boris
Publication year - 2010
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/emboj.2010.253
Subject(s) - hyperpolarization (physics) , biology , cyclic nucleotide , microbiology and biotechnology , apoptosis , potassium channel , nucleotide , biophysics , biochemistry , gene , nuclear magnetic resonance spectroscopy , stereochemistry , chemistry
Cellular calcium uptake is a controlled physiological process mediated by multiple ion channels. The exposure of cells to either one of the protein kinase C (PKC) inhibitors, staurosporine (STS) or PKC412, can trigger Ca 2+ influx leading to cell death. The precise molecular mechanisms regulating these events remain elusive. In this study, we report that the PKC inhibitors induce a prolonged Ca 2+ import through hyperpolarization‐activated cyclic nucleotide‐gated channel 2 (HCN2) in lung carcinoma cells and in primary culture of cortical neurons, sufficient to trigger apoptosis‐inducing factor (AIF)‐mediated apoptosis. Downregulation of HCN2 prevented the drug‐induced Ca 2+ increase and subsequent apoptosis. Importantly, the PKC inhibitors did not cause Ca 2+ entry into HEK293 cells, which do not express the HCN channels. However, introduction of HCN2 sensitized them to STS/PKC412‐induced apoptosis. Mutagenesis of putative PKC phosphorylation sites within the C‐terminal domain of HCN2 revealed that dephosphorylation of Thr 549 was critical for the prolonged Ca 2+ entry required for AIF‐mediated apoptosis. Our findings demonstrate a novel role for the HCN2 channel by providing evidence that it can act as an upstream regulator of cell death triggered by PKC inhibitors.