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Bcl-2-like protein 1; Bcl2-L-1; apoptosis regulator Bcl-X (BCL2L1, BCL2L, BCLX)

Function: - depending upon the alternatively spliced form, inhibits (Bcl-XL) or enhances (Bcl-XS) apoptosis - Bcl-XL is a potent inhibitor of cell death - isoform Bcl-XL anti-apoptotic activity is inhibited by association with SIVA isoform 1 - inhibits activation of caspases (putative) - appears to regulate cell death by blocking the voltage-dependent anion channnel (VDAC) by binding to it & preventing the release of the caspase activator, cytochrome c, from the mitochondrial membrane - the Bcl-XS isoform promotes apoptosis - proteolytically cleaved by caspases during apoptosis - the cleaved protein, lacking the BH4 motif, has pro-apoptotic activity - Bcl-XL forms homodimers, & heterodimers with BAX, BAK & BCL2 - heterodimerization with BAX does not seem to be required for anti-apoptotic activity - also interacts with BAD & BBC3 - isoform Bcl-XL binds to Siva isoform 1 - interacts with BCL2L11 (putative) - interacts with BECN1 & PGAM5 Structure: - the BH4 motif is required for anti-apoptotic activity - the BH1 & BH2 motifs are required for both heterodimerization with other Bcl-2 family members & for repression of cell death - belongs to the Bcl-2 family Compartment: - mitochondrial membrane, nuclear membrane - mitochondrial membranes & perinuclear envelope, cytoplasmic side (putative) Alternative splicing: named isoforms=3; Bcl-XL, Bcl-XS, Bcl-X(beta) Expression: - Bcl-XS is expressed at high levels in cells that undergo a high rate of turnover, such as developing lymphocytes - in contrast, Bcl-XL is found in tissues containing long-lived postmitotic cells, such as adult brain

Related

bcl-x proto-oncogene

Specific

bcl-x gamma bcl-xL bcl-xS

General

bcl-2 subfamily protein proto oncogene protein

Properties

SIZE: entity length = 233 aa MW = 26 kD COMPARTMENT: mitochondria cytoplasm nuclear membrane MOTIF: BH4 {4-24} peptide motif {61-62} BH3 {86-100} BH1 {129-148} BH2 {180-195} transmembrane domain {210-226}

Database Correlations

OMIM 600039 UniProt Q07817 PFAM correlations Entrez Gene 598 KEGG correlations

References

  1. UniProt :accession Q07817
  2. Boise LH et al bcl-x, a bcl-2-related gene that functions as a dominant regulator of apoptotic cell death. Cell. 1993 Aug 27;74(4):597-608. PMID: 8358789