Mitogen-activated protein kinase kinase kinase 3 is an enzyme that in humans is encoded by the MAP3K3 gene, [5] which is located on the long arm of chromosome 17 (17q23.3). [6]
Mitogen-activated protein kinase kinase kinase 3 is an enzyme that in humans is encoded by the MAP3K3 gene, [5] which is located on the long arm of chromosome 17 (17q23.3). [6]
This gene product is a 626-amino acid polypeptide that is 96.5% identical to mouse MEKK3. Its catalytic domain is closely related to those of several other kinases, including mouse MEKK2, tobacco NPK, and yeast STE11. Northern blot analysis revealed a 4.6-kb transcript that appears to be ubiquitously expressed.
MAP3Ks are involved in regulating cell fate in response to external stimuli. [7] MAP3K3 directly regulates the stress-activated protein kinase (SAPK) and extracellular signal-regulated protein kinase (ERK) pathways by activating SEK and MEK1/2 respectively. In cotransfection assays, it enhanced transcription from a nuclear factor kappa-B (NF-κB)-dependent reporter gene, consistent with a role in the SAPK pathway. Alternatively spliced transcript variants encoding distinct isoforms have been observed. [8] MEKK3 regulates the p38, JNK and ERK1/2 pathways. [7]
MAP3K3 has been shown to interact with [SQSTM1/p62],:
Two SNPs in the MAP3K3 gene were found as candidates for association with colon and rectal cancers. [15]
MEKK3 is highly expressed in 4 ovarian cancer cell lines (OVCA429, Hey, DOV13, and SKOv3). This expression level is significantly higher in those cancer cells when compared to normal cells. MEKK3 expression levels are comparable to IKK kinase activities, which also relate to activation of NFκB. High expression of MEKK3 in most of these ovarian cancer cells supposedly activate IKK kinase activity, which lead to increased levels of active NFκB. Also, MEKK3 interacts with AKT to activate NFκB. Genes related to cell survival and anti-apoptosis have increased expression in most cancer cells with high levels of MEKK3. This is probably due to constitutive activation of NFκB, which will regulate those genes. In this sense, knockdown of MEKK3 caused ovarian cancer cells to be more sensitive to drugs. [10]
MEKK3 also interacts with BRCA1. Knocking down BRCA1 resulted in inhibited MEKK3 kinase activity. The drug paclitaxel induces MEKK3 activity and it requires functional BRCA1 to do it. It was observed that in a breast cancer cell line BRCA1-deficient (HCC1937), paclitaxel was unable to activate MEKK3. Paclitaxel may be inducing stress-response through the MEKK3/JNK/p38/MAPK pathway, but not in mutated BRCA1 cells. [9]
A mitogen-activated protein kinase is a type of protein kinase that is specific to the amino acids serine and threonine. MAPKs are involved in directing cellular responses to a diverse array of stimuli, such as mitogens, osmotic stress, heat shock and proinflammatory cytokines. They regulate cell functions including proliferation, gene expression, differentiation, mitosis, cell survival, and apoptosis.
Mitogen Activated Protein (MAP) kinase kinase kinase, MAPKKK is a serine/threonine-specific protein kinase which acts upon MAP kinase kinase. Subsequently, MAP kinase kinase activates MAP kinase. Several types of MAPKKK can exist but are mainly characterized by the MAP kinases they activate. MAPKKKs are stimulated by a large range of stimuli, primarily environmental and intracellular stressors. MAPKKK is responsible for various cell functions such as cell proliferation, cell differentiation, and apoptosis. The duration and intensity of signals determine which pathway ensues. Additionally, the use of protein scaffolds helps to place the MAPKKK in close proximity with its substrate to allow for a reaction. Lastly, because MAPKKK is involved in a series of several pathways, it has been used as a therapeutic target for cancer, amyloidosis, and neurodegenerative diseases. In humans, there are at least 19 genes which encode MAP kinase kinase kinases:
In molecular biology, extracellular signal-regulated kinases (ERKs) or classical MAP kinases are widely expressed protein kinase intracellular signalling molecules that are involved in functions including the regulation of meiosis, mitosis, and postmitotic functions in differentiated cells. Many different stimuli, including growth factors, cytokines, virus infection, ligands for heterotrimeric G protein-coupled receptors, transforming agents, and carcinogens, activate the ERK pathway.
RAF kinases are a family of three serine/threonine-specific protein kinases that are related to retroviral oncogenes. The mouse sarcoma virus 3611 contains a RAF kinase-related oncogene that enhances fibrosarcoma induction. RAF is an acronym for Rapidly Accelerated Fibrosarcoma.
U0126 is a highly selective inhibitor of both MEK1 and MEK2, a type of MAPK/ERK kinase. U0126 was found to functionally antagonize AP-1 transcriptional activity via noncompetitive inhibition of the dual specificity kinase MEK with IC50 of 72 nM for MEK1 and 58 nM for MEK2. U0126 inhibited anchorage-independent growth of Ki-ras-transformed rat fibroblasts by simultaneously blocking both extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR)-p70(S6K) pathways. The effects of U0126 on the growth of eight human breast cancer cell lines shown that U0126 selectively repressed anchorage-independent growth of MDA-MB231 and HBC4 cells, two lines with constitutively activated ERK. Loss of contact with substratum triggers apoptosis in many normal cell types, a phenomenon termed anoikis. U0126 sensitized MDA-MB231 and HBC4 to anoikis, i.e., upon treatment with U0126, cells deprived of anchorage entered apoptosis.
Apoptosis signal-regulating kinase 1 (ASK1) also known as mitogen-activated protein kinase 5 (MAP3K5) is a member of MAP kinase family and as such a part of mitogen-activated protein kinase pathway. It activates c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases in a Raf-independent fashion in response to an array of stresses such as oxidative stress, endoplasmic reticulum stress and calcium influx. ASK1 has been found to be involved in cancer, diabetes, rheumatoid arthritis, cardiovascular and neurodegenerative diseases.
Mitogen-activated protein kinase 1, also known as ERK2, is an enzyme that in humans is encoded by the MAPK1 gene.
Mitogen-activated protein kinase 3, also known as p44MAPK and ERK1, is an enzyme that in humans is encoded by the MAPK3 gene.
Dual specificity mitogen-activated protein kinase kinase 1 is an enzyme that in humans is encoded by the MAP2K1 gene.
Dual specificity mitogen-activated protein kinase kinase 2 is an enzyme that in humans is encoded by the MAP2K2 gene. It is more commonly known as MEK2, but has many alternative names including CFC4, MKK2, MAPKK2 and PRKMK2.
Dual-specificity mitogen-activated protein kinase kinase 4 is an enzyme that in humans is encoded by the MAP2K4 gene.
ETS Like-1 protein Elk-1 is a protein that in humans is encoded by the ELK1. Elk-1 functions as a transcription activator. It is classified as a ternary complex factor (TCF), a subclass of the ETS family, which is characterized by a common protein domain that regulates DNA binding to target sequences. Elk1 plays important roles in various contexts, including long-term memory formation, drug addiction, Alzheimer's disease, Down syndrome, breast cancer, and depression.
Mitogen-activated protein kinase 7 also known as MAP kinase 7 is an enzyme that in humans is encoded by the MAPK7 gene.
Dual specificity mitogen-activated protein kinase kinase 6 also known as MAP kinase kinase 6 or MAPK/ERK kinase 6 is an enzyme that in humans is encoded by the MAP2K6 gene, on chromosome 17.
Dual specificity mitogen-activated protein kinase kinase 3 is an enzyme that in humans is encoded by the MAP2K3 gene.
Mitogen-activated protein kinase kinase kinase 1 (MAP3K1) is a signal transduction enzyme that in humans is encoded by the autosomal MAP3K1 gene.
Mitogen-activated protein kinase kinase kinase 8 is an enzyme that in humans is encoded by the MAP3K8 gene.
Dual specificity mitogen-activated protein kinase kinase 5 is an enzyme that in humans is encoded by the MAP2K5 gene.
Mitogen-activated protein kinase kinase kinase 4 is an enzyme that in humans is encoded by the MAP3K4 gene.
Mitogen-Activated Protein Kinase Kinase Kinase 2 also known as MEKK2 is an enzyme that in humans is encoded by the MAP3K2 gene.
PDB gallery | |
|---|---|
|
