Cyclin-dependent kinase 4 inhibitor D is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...
that in humans is encoded by the ''CDKN2D''
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 ...
.
The
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, res ...
encoded by this
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 ...
is a member of the
INK4 family of cyclin-dependent kinase
inhibitors. This protein has been shown to form a stable complex with
CDK4 or
CDK6
Cell division protein kinase 6 (CDK6) is an enzyme encoded by the ''CDK6'' gene. It is regulated by cyclins, more specifically by Cyclin D proteins and Cyclin-dependent kinase inhibitor proteins. The protein encoded by this gene is a member of th ...
, and prevent the activation of the CDK
kinases
In biochemistry, a kinase () is an enzyme that catalyzes the transfer of phosphate groups from high-energy, phosphate-donating molecules to specific substrates. This process is known as phosphorylation, where the high-energy ATP molecule don ...
, thus function as a cell growth regulator that controls cell cycle
G1 progression. The abundance of the transcript of this gene was found to oscillate in a cell-cycle dependent manner with the lowest expression at mid G1 and a maximal expression during S phase. The negative regulation of the cell cycle involved in this protein was shown to participate in repressing
neuronal
A neuron, neurone, or nerve cell is an electrically excitable cell that communicates with other cells via specialized connections called synapses. The neuron is the main component of nervous tissue in all animals except sponges and placozoa. No ...
proliferation, as well as
spermatogenesis. The expression of this gene and its protein product (p19) is observed in neurons with
neurofibrillary tangles
Neurofibrillary tangles (NFTs) are aggregates of hyperphosphorylated tau protein that are most commonly known as a primary biomarker of Alzheimer's disease. Their presence is also found in numerous other diseases known as tauopathies. Little is ...
(NFTs) and it is suggested as a marker for senescent neurons.
Two alternatively spliced variants of this gene, which encode an identical protein, have been reported.
Note, this protein should not be confused with p19-ARF (mouse) or the human equivalent
p14ARF
p14ARF (also called ARF tumor suppressor, ARF, p14ARF) is an alternate reading frame protein product of the '' CDKN2A'' locus (i.e. ''INK4a''/''ARF'' locus). p14ARF is induced in response to elevated mitogenic stimulation, such as aberrant grow ...
, which are alternative products of the
CDKN2A
CDKN2A, also known as cyclin-dependent kinase inhibitor 2A, is a gene which in humans is located at chromosome 9, band p21.3. It is ubiquitously expressed in many tissues and cell types. The gene codes for two proteins, including the INK4 family ...
gene.
References
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External links
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Cell cycle regulators
{{gene-19-stub