Induced myeloid leukemia cell differentiation protein Mcl-1 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respon ...
that in humans is encoded by the ''MCL1''
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
.
Function
The protein encoded by this gene belongs to the
Bcl-2 family
The Bcl-2 familyTC# 1.A.21 consists of a number of evolutionarily-conserved proteins that share Bcl-2 homology (BH) domains. The Bcl-2 family is most notable for their regulation of apoptosis, a form of programmed cell death, at the mitochondri ...
. Alternative splicing occurs at this locus and two transcript variants encoding distinct isoforms have been identified. The longer gene product (isoform 1) enhances cell survival by inhibiting
apoptosis while the alternatively spliced shorter gene product (isoform 2) promotes apoptosis and is death-inducing. The protein MCL1 has a very short
biological half-life
Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the bl ...
of only 20–30 minutes.
The loss of MCL1 has a more dramatic impact than the loss of any other anti-apoptotic member of the Bcl-2 family. Loss of the ''Mcl-1'' gene results in embryo death when the embryo is only around 3.5 days old, before it has even implanted. Conditional deletion of ''Mcl-1'' depletes a wide variety of cells, including
hematopoietic stem cell
Hematopoietic stem cells (HSCs) are the stem cells that give rise to other blood cells. This process is called haematopoiesis. In vertebrates, the very first definitive HSCs arise from the ventral endothelial wall of the embryonic aorta withi ...
s, B cell–committed progenitors, T cell–committed progenitors, antibody-secreting plasma cells,
cardiac muscle cells, and
neuron
A neuron, neurone, or nerve cell is an membrane potential#Cell excitability, electrically excitable cell (biology), cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous ...
s.
Deletion of ''Mcl-1'' in hepatocytes causes apoptosis and aberrant polyploidization but improves liver regeneration after surgery. MCL1 works synergistically with p53 in protecting liver from injury, fibrosis and cancer.
MCL1 also has a role in the cell's energy production, working in the
intermitochondrial space.
Clinical significance
Omacetaxine mepesuccinate
Omacetaxine mepesuccinate (INN, trade names Synribo ), formerly named as homoharringtonine or HHT, is a pharmaceutical drug substance that is indicated for treatment of chronic myeloid leukemia (CML).
HHT is a natural plant alkaloid derived from ...
(a drug approved for the treatment for
chronic myelogenous leukemia
Chronic myelogenous leukemia (CML), also known as chronic myeloid leukemia, is a cancer of the white blood cells. It is a form of leukemia characterized by the increased and unregulated growth of myeloid cells in the bone marrow and the accumula ...
) and
Seliciclib (which is under investigation as a potential
multiple myeloma
Multiple myeloma (MM), also known as plasma cell myeloma and simply myeloma, is a cancer of plasma cells, a type of white blood cell that normally produces antibodies. Often, no symptoms are noticed initially. As it progresses, bone pain, ane ...
treatment) both act in part by inhibiting synthesis of Mcl-1. MCL1 has been identified as a resistance factor for BCL-2 inhibitor venetoclax in lymphoma cells. Therefore, new strategies of combining BCL-2 and MCL1 inhibitors are currently under clinical trials for several tumor types.
Interactions
MCL1 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization using innovative strategies to advocate for the legal and human rights of children with intersex traits. The organizat ...
with:
*
BAK1,
*
BCL2L11
Bcl-2-like protein 11, commonly called BIM (Bcl-2 Interacting Mediator of cell death), is a protein that in humans is encoded by the ''BCL2L11'' gene.
Function
The protein encoded by this gene belongs to the BCL-2 protein family. BCL-2 fami ...
,
[
* BAD,]PCNA
Proliferating cell nuclear antigen (PCNA) is a DNA clamp that acts as a processivity factor for DNA polymerase δ in eukaryotic cells and is essential for replication. PCNA is a homotrimer and achieves its processivity by encircling the DNA, ...
,
See also
*Bcl-2
Bcl-2 (B-cell lymphoma 2), encoded in humans by the ''BCL2'' gene, is the founding member of the Bcl-2 family of regulator proteins that regulate cell death ( apoptosis), by either inhibiting (anti-apoptotic) or inducing (pro-apoptotic) apoptosi ...
*Bcl-xL
B-cell lymphoma-extra large (Bcl-xL), encoded by the BCL2-like 1 gene, is a transmembrane molecule in the mitochondria. It is a member of the Bcl-2 family of proteins, and acts as an anti-apoptotic protein by preventing the release of mitochond ...
References
Further reading
*
External links
*
{{PDB Gallery, geneid=4170