The BNIP-2 and Cdc42GAP Homology/Sec14p-like Domain of BNIP-Sα Is a Novel Apoptosis-inducing Sequence

Yi Ting Zhou, Unice J. K. Soh, Xun Shang, Graeme R. Guy, Boon Chuan Low
2001 Journal of Biological Chemistry  
We have cloned the cDNAs for two novel human proteins, designated BNIP-S␣ and ␤ (for BNIP-2 Similar) that are homologous to BNIP-2, a previously known Bcl-2 and E1B-associated protein. The BNIP-S gene encodes two protein isoforms; the longer protein (BNIP- S␣) contains a complete BNIP-2 and Cdc42GAP Homology (BCH) domain, a novel protein domain that we recently identified, whereas its shorter variant (BNIP-S␤) lacks the full BCH domain as a result of an alternative RNA splicing that introduces
more » ... nonsense intron. Primer-specific reverse-transcription PCR revealed that both BNIP-S␣ and BNIP-S␤ mRNA are differentially expressed in various cells and tissues. The expression of BNIP-S␣ or the complete BCH domain, but not BNIP-S␤, causes extensive apoptosis in cells. Furthermore, BNIP-S␣ can form a homophilic complex via a unique sequence motif within its BCH domain, and deletion of this interacting motif prevents its pro-apoptotic effect. These results indicate the presence of two BNIP-S splicing variants as cellular regulators and that the BCH domain of BNIP-S␣ confers a novel apoptotic function. The significance of this is discussed.
doi:10.1074/jbc.m109459200 pmid:11741952 fatcat:no4ndwjf7nbw5m4362ahv4hmzu