Identification of a dominant negative functional domain on DAPK-1 that degrades DAPK-1 protein and stimulates TNFR-1-mediated apoptosis.

Lin, Yao; Stevens, Craig; Hupp, Ted

Abstract

DAPK-1 is a stress-activated tumor suppressor protein that plays a role in both proapoptotic or antiapoptotic signal transduction pathways. To define mechanisms of DAPK-1 protein regulation, we have determined that DAPK-1 protein has a long half-life, and therefore its activity is primarily regulated at the protein level. Changes in DAPK-1 protein levels occur by a cathepsin B-dependent pathway, prompting us to evaluate whether cathepsin B plays positive or negative role in DAPK-1 function. The transfection of p55-TNFR-1 induced complex formation between DAPK-1 and cathepsin B. Depletion of cathepsin B protein using small interfering RNA stimulated TNFR-1 dependent apoptosis. The minimal binding region on DAPK-1 for cathepsin B was mapped to amino acids 836–947. The transfection of the DAPK-1-(836–947) miniprotein acted in a dominant negative manner inducing endogenous DAPK-1 protein degradation in a TNFR-1-dependent manner. These data suggest that DAPK-1 forms a multiprotein survival complex with cathepsin B countering the rate of TNFR-1-dependent apoptosis and highlights the importance of developing DAPK-1 inhibitors as agents to sensitize cells to stress-induced apoptosis.

• Journal Article Type: Article
• Online Publication Date: Feb 26, 2007
• Publication Date: Jun 8, 2007
• Deposit Date: Aug 2, 2016
• Journal: Journal of Biological Chemistry
• Print ISSN: 0021-9258
• Electronic ISSN: 1083-351X
• Publisher: American Society for Biochemistry and Molecular Biology
• Peer Reviewed: Peer Reviewed
• Volume: 282
• Issue: 23
• Pages: 16792-16802
• DOI: https://doi.org/10.1074/jbc.M611559200
• Keywords: DAPK-1, tumor suppressor protein, signal transduction pathways, protein regulation,
• Public URL: http://researchrepository.napier.ac.uk/Output/322308