title: JNK1/2 regulate Bid by direct phosphorylation at Thr59 in response to ALDH1L1.
abstract: BH3 interacting-domain death agonist (Bid) is a BH3-only pro-apoptotic member of the Bcl-2 family of proteins. Its function in apoptosis is associated with the proteolytic cleavage to the truncated form tBid, mainly by caspase-8. tBid translocates to mitochondria and assists Bax and Bak in induction of apoptosis. c-Jun N-terminal kinase (JNK)-dependent alternative processing of Bid to jBid was also reported. We have previously shown that the folate stress enzyme 10-formyltetrahydrofolate dehydrogenase (ALDH1L1) activates JNK1 and JNK2 in cancer cells as a pro-apoptotic response. Here we report that in PC-3 prostate cancer cells, JNK1/2 phosphorylate Bid at Thr59 within the caspase cleavage site in response to ALDH1L1. In vitro, all three JNK isoforms, JNK 1-3, phosphorylated Thr59 of Bid with JNK1 being the least active. Thr59 phosphorylation protected Bid from cleavage by caspase-8, resulting in strong accumulation of the full-length protein and its translocation to mitochondria. Interestingly, although we did not observe jBid in response to ALDH1L1 in PC-3 cells, transient expression of Bid mutants lacking the caspase-8 cleavage site resulted in strong accumulation of jBid. Of note, a T59D mutant mimicking constitutive phosphorylation revealed more profound cleavage of Bid to jBid. JNK-driven Bid accumulation had a pro-apoptotic effect in our study: small interfering RNA silencing of either JNK1/2 or Bid prevented Bid phosphorylation and accumulation, and rescued ALDH1L1-expressing cells. As full-length Bid is a weaker apoptogen than tBid, we propose that the phosphorylation of Bid by JNKs, followed by the accumulation of the full-length protein, delays attainment of apoptosis, and allows the cell to evaluate the stress and make a decision regarding the response strategy. This mechanism perhaps can be modified by the alternative cleavage of phospho-T59 Bid to jBid at some conditions.
authors: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA.
authors: A
authors: A
authors: Prakasam
authors: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA.
authors: S
authors: S
authors: Ghose
authors: Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA.
authors: N V
authors: NV
authors: Oleinik
authors: Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, SC, USA.
authors: J R
authors: JR
authors: Bethard
authors: Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, USA.
authors: Y K
authors: YK
authors: Peterson
authors: 1] Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA [2] Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA.
authors: N I
authors: NI
authors: Krupenko
authors: 1] Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC, USA [2] Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, USA.
authors: S A
authors: SA
authors: Krupenko
mesh_terms: D000444:Aldehyde Dehydrogenase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D051023:BH3 Interacting Domain Death Agonist Protein / Q000235:genetics / Q000378:metabolism*; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D006801:Humans; D008297:Male; D048055:Mitogen-Activated Protein Kinase 8 / Q000235:genetics / Q000378:metabolism*; D048056:Mitogen-Activated Protein Kinase 9 / Q000235:genetics / Q000378:metabolism*; D000587:Oxidoreductases Acting on CH-NH Group Donors; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000201:enzymology* / Q000235:genetics; D013912:Threonine / Q000235:genetics / Q000378:metabolism; D000099295:Formyltetrahydrofolate Dehydrogenase
chemical_list: D000444:Aldehyde Dehydrogenase; D051023:BH3 Interacting Domain Death Agonist Protein; D053181:Caspase 8; D048055:Mitogen-Activated Protein Kinase 8; D048056:Mitogen-Activated Protein Kinase 9; D000587:Oxidoreductases Acting on CH-NH Group Donors; D013912:Threonine; D000099295:Formyltetrahydrofolate Dehydrogenase