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Am J Hum Genet. 2011 Jul 15;89(1):56-66. doi: 10.1016/j.ajhg.2011.05.027. Epub 2011 Jun 30.

Functional mutation of SMAC/DIABLO, encoding a mitochondrial proapoptotic protein, causes human progressive hearing loss DFNA64.

Author information

1
Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China.

Abstract

SMAC/DIABLO is a mitochondrial proapoptotic protein that is released from mitochondria during apoptosis and counters the inhibitory activities of inhibitor of apoptosis proteins, IAPs. By linkage analysis and candidate screening, we identified a heterozygous SMAC/DIABLO mutation, c.377C>T (p.Ser126Leu, refers to p.Ser71Leu in the mature protein) in a six-generation Chinese kindred characterized by dominant progressive nonsyndromic hearing loss, designated as DFNA64. SMAC/DIABLO is highly expressed in human embryonic ears and is enriched in the developing mouse inner-ear hair cells, suggesting it has a role in the development and homeostasis of hair cells. We used a functional study to demonstrate that the SMAC/DIABLO(S71L) mutant, while retaining the proapoptotic function, triggers significant degradation of both wild-type and mutant SMAC/DIABLO and renders host mitochondria susceptible to calcium-induced loss of the membrane potential. Our work identifies DFNA64 as the human genetic disorder associated with SMAC/DIABLO malfunction and suggests that mutant SMAC/DIABLO(S71L) might cause mitochondrial dysfunction.

PMID:
21722859
PMCID:
PMC3135809
DOI:
10.1016/j.ajhg.2011.05.027
[Indexed for MEDLINE]
Free PMC Article

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