Journal Article

JNK1/2 regulate Bid by direct phosphorylation at Thr59 in response to ALDH1L1

Peterson, Y K, Krupenko, N I, Krupenko, S A, Ghose, S, Bethard, J R, Prakasam, A, Oleinik, N V

2014

Overview

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.

• Publisher: Nature Publishing Group UK,Springer Nature B.V,Nature Publishing Group
• Subject: 631/80/82/23 / 631/80/86 / 692/699/67/589/466 / Aldehyde Dehydrogenase - chemistry / Aldehyde Dehydrogenase - genetics / Aldehyde Dehydrogenase - metabolism / Amino Acid Motifs / Antibodies / BH3 Interacting Domain Death Agonist Protein - genetics / BH3 Interacting Domain Death Agonist Protein - metabolism / Biochemistry / Biomedical and Life Sciences / Caspase 8 - metabolism / Cell Biology / Cell Culture / Cell Line, Tumor / Humans / Immunology / Life Sciences / Male / Mitogen-Activated Protein Kinase 8 - genetics / Mitogen-Activated Protein Kinase 8 - metabolism / Mitogen-Activated Protein Kinase 9 - genetics / Mitogen-Activated Protein Kinase 9 - metabolism / Original / original-article / Phosphorylation / Prostatic Neoplasms - enzymology / Prostatic Neoplasms - genetics / Threonine - genetics / Threonine - metabolism