Mitogen-activated protein kinase 8 (also known as JNK1) is a ubiquitous
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
that in humans is encoded by the ''MAPK8''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
Function
The protein encoded by this gene is a member of the
MAP kinase
A mitogen-activated protein kinase (MAPK or MAP kinase) is a type of serine/threonine-specific protein kinases involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflammato ...
and
JNK family. MAP kinases act as an integration point for multiple biochemical signals, and are involved in a wide variety of cellular processes such as
proliferation,
differentiation, transcription regulation and development. This kinase is activated by various cell stimuli, and targets specific
transcription factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription (genetics), transcription of genetics, genetic information from DNA to messenger RNA, by binding t ...
s, and thus mediates immediate-early
gene expression
Gene expression is the process (including its Regulation of gene expression, regulation) by which information from a gene is used in the synthesis of a functional gene product that enables it to produce end products, proteins or non-coding RNA, ...
in response to cell stimuli. The activation of this kinase by
tumor-necrosis factor alpha (TNF-alpha) is found to be required for TNF-alpha-induced
apoptosis
Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ...
. This
kinase
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 ...
is also involved in UV radiation-induced apoptosis, which is thought to be related to the
cytochrome c-mediated cell death pathway. Studies of the mouse counterpart of this gene suggested that this kinase play a key role in
T cell
T cells (also known as T lymphocytes) are an important part of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell receptor (TCR) on their cell ...
proliferation, apoptosis and differentiation. Four
alternately spliced transcript variants encoding distinct
isoform
A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu ...
s have been reported. MAPK8 contains multiple amino acid sites that are phosphorylated and ubiquitinated.
Interactions
MAPK8 has been shown to
interact with:
*
Activating transcription factor 2,
*
C-jun
Transcription factor Jun is a protein that in humans is encoded by the ''JUN'' gene. c-Jun, in combination with protein c-Fos, forms the AP-1 early response transcription factor. It was first identified as the Fos-binding protein p39 and only l ...
,
IRS1
Insulin receptor substrate 1 (IRS-1) is a signaling adapter protein that in humans is encoded by the ''IRS1'' gene. It is a 180 kDa protein with amino acid sequence of 1242 residues. It contains a single pleckstrin homology (PH) domain at the N-t ...
,ITCH
An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both ...
, MAP3K1
Mitogen-activated protein kinase kinase kinase 1 (MAP3K1) is a signal transduction enzyme that in humans is encoded by the autosomal ''MAP3K1'' gene.
Function
MAP3K1 (or MEKK1) is a serine/threonine kinase and ubiquitin ligase that performs a ...
[
* MAPK8IP1,]Myc
''Myc'' is a family of regulator genes and proto-oncogenes that code for transcription factors. The ''Myc'' family consists of three related human genes: ''c-myc'' ( MYC), ''l-myc'' ( MYCL), and ''n-myc'' ( MYCN). ''c-myc'' (also sometimes r ...
,
References
Further reading
*
*
*
External links
MAP Kinase Resource
.
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EC 2.7.11