MAP2K1 phospho S298
Domain
The proline-rich region localized between residues 270 and 307 is important for binding to RAF1 and activation of MAP2K1/MEK1.
Function
Dual specificity protein kinase which acts as an essential component of the MAP kinase signal transduction pathway. Binding of extracellular ligands such as growth factors, cytokines and hormones to their cell-surface receptors activates RAS and this initiates RAF1 activation. RAF1 then further activates the dual-specificity protein kinases MAP2K1/MEK1 and MAP2K2/MEK2. Both MAP2K1/MEK1 and MAP2K2/MEK2 function specifically in the MAPK/ERK cascade, and catalyze the concomitant phosphorylation of a threonine and a tyrosine residue in a Thr-Glu-Tyr sequence located in the extracellular signal-regulated kinases MAPK3/ERK1 and MAPK1/ERK2, leading to their activation and further transduction of the signal within the MAPK/ERK cascade. Activates BRAF in a KSR1 or KSR2-dependent manner; by binding to KSR1 or KSR2 releases the inhibitory intramolecular interaction between KSR1 or KSR2 protein kinase and N-terminal domains which promotes KSR1 or KSR2-BRAF dimerization and BRAF activation (PubMed:29433126). Depending on the cellular context, this pathway mediates diverse biological functions such as cell growth, adhesion, survival and differentiation, predominantly through the regulation of transcription, metabolism and cytoskeletal rearrangements. One target of the MAPK/ERK cascade is peroxisome proliferator-activated receptor gamma (PPARG), a nuclear receptor that promotes differentiation and apoptosis. MAP2K1/MEK1 has been shown to export PPARG from the nucleus. The MAPK/ERK cascade is also involved in the regulation of endosomal dynamics, including lysosome processing and endosome cycling through the perinuclear recycling compartment (PNRC), as well as in the fragmentation of the Golgi apparatus during mitosis.
Involvement in disease
Cardiofaciocutaneous syndrome 3
CFC3
A form of cardiofaciocutaneous syndrome, a multiple congenital anomaly disorder characterized by a distinctive facial appearance, heart defects and intellectual disability. Heart defects include pulmonic stenosis, atrial septal defects and hypertrophic cardiomyopathy. Some affected individuals present with ectodermal abnormalities such as sparse, friable hair, hyperkeratotic skin lesions and a generalized ichthyosis-like condition. Typical facial features are similar to Noonan syndrome. They include high forehead with bitemporal constriction, hypoplastic supraorbital ridges, downslanting palpebral fissures, a depressed nasal bridge, and posteriorly angulated ears with prominent helices. Distinctive features of CFC3 include macrostomia and horizontal shape of palpebral fissures.
None
The disease is caused by variants affecting the gene represented in this entry.
Melorheostosis, isolated
MEL
A sclerosing bone disorder characterized by hyperostosis of the cortex of tubular bones, frequently involving one limb. The lesions may be accompanied by abnormalities of adjacent soft tissue, joint contractures, sclerodermatous skin lesions, muscle atrophy, or hemangioma.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
Phosphorylation at Ser-218 and Ser-222 by MAP kinase kinase kinases (BRAF or MEKK1) positively regulates kinase activity (PubMed:29433126, PubMed:8131746). Also phosphorylated at Thr-292 by MAPK1/ERK2 and at Ser-298 by PAK (PubMed:16129686). MAPK1/ERK2 phosphorylation of Thr-292 occurs in response to cellular adhesion and leads to inhibition of Ser-298 phosphorylation by PAK (PubMed:16129686). Autophosphorylated at Ser-218 and Ser-222, autophosphosphorylation is promoted by NEK10 following UV irradiation (PubMed:20956560).
(Microbial infection) Acetylation by Yersinia YopJ prevents phosphorylation and activation, thus blocking the MAPK signaling pathway.
Sequence Similarities
Belongs to the protein kinase superfamily. STE Ser/Thr protein kinase family. MAP kinase kinase subfamily.
Tissue Specificity
Widely expressed, with extremely low levels in brain.
Cellular localization
- Cytoplasm
- Cytoskeleton
- Microtubule organizing center
- Centrosome
- Cytoplasm
- Cytoskeleton
- Microtubule organizing center
- Spindle pole body
- Cytoplasm
- Nucleus
- Membrane
- Peripheral membrane protein
- Localizes at centrosomes during prometaphase, midzone during anaphase and midbody during telophase/cytokinesis (PubMed:14737111). Membrane localization is probably regulated by its interaction with KSR1 (PubMed:10409742).
Alternative names
MEK1, PRKMK1, MAP2K1, Dual specificity mitogen-activated protein kinase kinase 1, MAP kinase kinase 1, MAPKK 1, MKK1, ERK activator kinase 1, MAPK/ERK kinase 1, MEK 1