BCL2L13 | |||||||||||||||||||||||||||||||||||||||||||||||||||
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Identifiers | |||||||||||||||||||||||||||||||||||||||||||||||||||
Aliases | BCL2L13 , BCL-RAMBO, Bcl2-L-13, MIL1, BCL2 like 13 | ||||||||||||||||||||||||||||||||||||||||||||||||||
External IDs | MGI: 2136959; HomoloGene: 9111; GeneCards: BCL2L13; OMA:BCL2L13 - orthologs | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Wikidata | |||||||||||||||||||||||||||||||||||||||||||||||||||
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BCL2-like 13 (apoptosis facilitator), also known as BCL2L13 or Bcl-rambo, is a protein which in humans is encoded by the BCL2L13 gene on chromosome 22. This gene encodes a mitochondrially-localized protein which is classified under the Bcl-2 protein family. Overexpression of the encoded protein results in apoptosis. [5] [6] As a result, it has been implicated in cancers such as childhood acute lymphoblastic leukemia (ALL) and glioblastoma multiforme (GBM). [7] [8] Alternatively spliced transcript variants have been observed for this gene, such as Bcl-rambo beta. [5] [9]
As a member of the Bcl-2 protein family, Bcl-rambo comprises four conserved BH domains and a transmembrane (TM) domain. However, unlike the other members, Bcl-rambo does not require the BH domains for its apoptotic function, relying instead on the mitochondrial localization carried out by the TM domain. In addition to these domains, it has conserved B-cell lymphoma 2 homology motifs, as well as an extension at its c-terminal, termed the BHNo domain, which contains two tandem repeats, RTA and RTB. [5] [9]
An alternatively-spliced protein variant, called Bcl-rambo beta, is composed of only the BH4 domain, completely lacking the BH domains 1 through 3 due to an in-frame stop codon inserted by an Alu element. Without the TM domain, this variant remains in the cytosol and does not localize to the mitochondria. Nonetheless, it still performs proapoptotic activity, mediated by the encoded Alu element, though the exact mechanisms remain to be elucidated. [10]
Bcl-rambo is a member of the Bcl-2 family of proteins that regulate apoptosis. In cells, Bcl-rambo is localized to the mitochondria, and its overexpression induces apoptosis that is blocked by caspase inhibitors, whereas inhibitors controlling upstream events of either the 'death receptor' (FLIP, FADD-DN) or the 'mitochondrial' pro-apoptotic pathway (Bcl-x(L)) had no effect. [6] Bcl-rambo mediates apoptosis by associating with adenine nucleotide translocator (ANT), a component of the mitochondrial permeability transition pore, to induce its opening. ANT will also facilitate the transfer of ADP and ATP between the cytosol and the matrix. [9]
The BCL2L13 gene has been implicated in a wide spectrum of cancers. Previous clinical studies observed in ALL patients that high expression of BCL2L13 correlated to lower event-free and overall survival. Though statistically significant, the observations contradict the accepted pro-apoptotic function of BCL2L13’s gene product, which should have contributed to cancer cell death and, thus, more favorable survival outcomes. Two possible explanations propose that either 1) Bcl-rambo performs a different biological role in childhood, or 2) alternative splicing could have generated an anti-apoptotic variant. More research is necessary to resolve this discrepancy. [7] In another type of cancer, GBM, Bcl-rambo is known to inhibit induced apoptosis in GBM cells by binding two other pro-apoptotic proteins, ceramide synthases 2 (CerS2) and 6 (CerS6), thereby blocking CerS2/6 complex formation and activity. Thus, inhibiting BCL2L13 during cancer treatments may improve survival outcomes. [8]
BCL2L13 has been shown to interact with:
Bcl-2, encoded in humans by the BCL2 gene, is the founding member of the Bcl-2 family of regulator proteins. BCL2 blocks programmed cell death (apoptosis) while other BCL2 family members can either inhibit or induce it. It was the first apoptosis regulator identified in any organism.
Apoptosis regulator BAX, also known as bcl-2-like protein 4, is a protein that in humans is encoded by the BAX gene. BAX is a member of the Bcl-2 gene family. BCL2 family members form hetero- or homodimers and act as anti- or pro-apoptotic regulators that are involved in a wide variety of cellular activities. This protein forms a heterodimer with BCL2, and functions as an apoptotic activator. This protein is reported to interact with, and increase the opening of, the mitochondrial voltage-dependent anion channel (VDAC), which leads to the loss in membrane potential and the release of cytochrome c. The expression of this gene is regulated by the tumor suppressor P53 and has been shown to be involved in P53-mediated apoptosis.
The BH3 interacting-domain death agonist, or BID, gene is a pro-apoptotic member of the Bcl-2 protein family. Bcl-2 family members share one or more of the four characteristic domains of homology entitled the Bcl-2 homology (BH) domains, and can form hetero- or homodimers. Bcl-2 proteins act as anti- or pro-apoptotic regulators that are involved in a wide variety of cellular activities.
Bcl-2 homologous antagonist/killer is a protein which in humans is encoded by the BAK1 gene on chromosome 6. It belongs to the BCL2 protein family. BCL2 family members form oligomers or heterodimers and act as anti- or pro-apoptotic regulators that are involved in a wide variety of cellular activities. This protein localizes to mitochondria, and functions to induce apoptosis. It interacts with and accelerates the opening of the mitochondrial voltage-dependent anion channel, which leads to a loss in membrane potential and the release of cytochrome c. This protein also interacts with the tumor suppressor P53 after exposure to cell stress.
The BCL2 associated agonist of cell death (BAD) protein is a pro-apoptotic member of the Bcl-2 gene family which is involved in initiating apoptosis. BAD is a member of the BH3-only family, a subfamily of the Bcl-2 family. It does not contain a C-terminal transmembrane domain for outer mitochondrial membrane and nuclear envelope targeting, unlike most other members of the Bcl-2 family. After activation, it is able to form a heterodimer with anti-apoptotic proteins and prevent them from stopping apoptosis.
Bcl-2-like protein 1 is a protein encoded in humans by the BCL2L1 gene. Through alternative splicing, the gene encodes both of the human proteins Bcl-xL and Bcl-xS.
Induced myeloid leukemia cell differentiation protein Mcl-1 is a protein that in humans is encoded by the MCL1 gene.
BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 is a protein found in humans that is encoded by the BNIP3 gene.
Bcl-2-like protein 11, commonly called BIM, is a protein that in humans is encoded by the BCL2L11 gene.
Bcl-2-related protein A1 is a protein in humans which is encoded by the BCL2A1 gene.
Bcl-2-interacting killer is a protein that in humans is encoded by the BIK gene.
Apoptosis regulatory protein Siva is a protein that in humans is encoded by the SIVA1 gene. This gene encodes a protein with an important role in the apoptotic pathway induced by the CD27 antigen, a member of the tumor necrosis factor receptor (TFNR) superfamily. The CD27 antigen cytoplasmic tail binds to the N-terminus of this protein. Two alternatively spliced transcript variants encoding distinct proteins have been described.
BCL2/adenovirus E1B 19 kDa protein-interacting protein 3-like is a protein that in humans is encoded by the BNIP3L gene.
Activator of apoptosis harakiri is a protein that in humans is encoded by the HRK gene.
Bcl-2-modifying factor is a protein that in humans is encoded by the BMF gene.
BCL2/adenovirus E1B 19 kDa protein-interacting protein 2 is a protein that in humans is encoded by the BNIP2 gene.
Apoptosis facilitator Bcl-2-like protein 14 is a protein that in humans is encoded by the BCL2L14 gene.
Bok is a protein-coding gene of the Bcl-2 family that is found in many invertebrates and vertebrates. It induces apoptosis, a special type of cell death. Currently, the precise function of Bok in this process is unknown.
Bcl-2-like protein 10 is a protein that in humans is encoded by the BCL2L10 gene.
Bcl-2-like protein 12 is a protein that in humans is encoded by the BCL2L12 gene.