Xiao K, Chen P, Chang DC. The VTLISFG motif in the BH1 domain plays a significant role in regulating the degradation of Mcl-1.
FEBS Open Bio 2014;
4:147-52. [PMID:
24490139 PMCID:
PMC3907746 DOI:
10.1016/j.fob.2014.01.006]
[Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 01/16/2014] [Accepted: 01/16/2014] [Indexed: 11/26/2022] Open
Abstract
Mcl-1 is a member of the Bcl-2 family protein; its degradation is required for the initiation of apoptosis. The mechanism, however, is not yet clearly known. Previously, it was reported that Mcl-1 is degraded through the ubiquitination-mediated pathway and the PEST domain is the motif responsible for promoting this degradation. We found evidence that this may not be true. We generated several Mcl-1 deletion mutants and examined their effects on protein stability. Deletion of the PEST domain did not prevent the degradation of Mcl-1 during apoptosis. The BH1 domain, but not the PEST, BH3 or BH2 domain, exhibited a short half-life. A peptide named “F3” (VTLISFG) in the C-terminus of the BH1 domain appears to be critical for the rapid turnover of Mcl-1. Deletion of F3 from GFP-Mcl-1-ΔPEST retarded the degradation of this mutant. F3 appeared to be the minimum functional sequence of the degradation motif, since deletion of a single residue was sufficient to abrogate its short half-life. Fusion of F3 with p32 resulted in the degradation of p32 during UV-induced apoptosis, while wild type p32 was not affected. Taken together, these findings suggest that F3 (VTLISFG), instead of PEST, is the major motif responsible for the degradation of Mcl-1 during apoptosis.
The PEST domain may not be responsible for the short half-life of Mcl-1 during apoptosis.
A short peptide (F3) inside the BH1 domain was found to have a short half-life.
Fusion of F3 with p32 impairs the stability of p32 during apoptosis.
Deletion of F3 increases the stability of GFP-Mcl-1-ΔPEST.
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