MAPKAPK3

This gene encodes a member of the Ser/Thr protein kinase family. This kinase functions as a mitogen-activated protein kinase (MAP kinase)- activated protein kinase. MAP kinases are also known as extracellular signal-regulated kinases (ERKs), act as an integration point for multiple biochemical signals. This kinase was shown to be activated by growth inducers and stress stimulation of cells. In vitro studies demonstrated that ERK, p38 MAP kinase and Jun N-terminal kinase were all able to phosphorylate and activate this kinase, which suggested the role of this kinase as an integrative element of signaling in both mitogen and stress responses. This kinase was reported to interact with, phosphorylate and repress the activity of E47, which is a basic helix-loop-helix transcription factor known to be involved in the regulation of tissue-specific gene expression and cell differentiation. Alternate splicing results in multiple transcript variants that encode the same protein. [provided by RefSeq, Sep 2011]

Full Name

Mitogen-Activated Protein Kinase-Activated Protein Kinase 3

Function

Stress-activated serine/threonine-protein kinase involved in cytokines production, endocytosis, cell migration, chromatin remodeling and transcriptional regulation. Following stress, it is phosphorylated and activated by MAP kinase p38-alpha/MAPK14, leading to phosphorylation of substrates. Phosphorylates serine in the peptide sequence, Hyd-X-R-X(2)-S, where Hyd is a large hydrophobic residue. MAPKAPK2 and MAPKAPK3, share the same function and substrate specificity, but MAPKAPK3 kinase activity and level in protein expression are lower compared to MAPKAPK2. Phosphorylates HSP27/HSPB1, KRT18, KRT20, RCSD1, RPS6KA3, TAB3 and TTP/ZFP36. Mediates phosphorylation of HSP27/HSPB1 in response to stress, leading to dissociate HSP27/HSPB1 from large small heat-shock protein (sHsps) oligomers and impair their chaperone activities and ability to protect against oxidative stress effectively. Involved in inflammatory response by regulating tumor necrosis factor (TNF) and IL6 production post-transcriptionally: acts by phosphorylating AU-rich elements (AREs)-binding proteins, such as TTP/ZFP36, leading to regulate the stability and translation of TNF and IL6 mRNAs. Phosphorylation of TTP/ZFP36, a major post-transcriptional regulator of TNF, promotes its binding to 14-3-3 proteins and reduces its ARE mRNA affinity leading to inhibition of dependent degradation of ARE-containing transcript. Involved in toll-like receptor signaling pathway (TLR) in dendritic cells: required for acute TLR-induced macropinocytosis by phosphorylating and activating RPS6KA3. Also acts as a modulator of Polycomb-mediated repression.

Biological Process

Intracellular signal transductionManual Assertion Based On ExperimentIBA:GO_Central
MacropinocytosisISS:UniProtKB
Peptidyl-serine phosphorylationManual Assertion Based On ExperimentIDA:BHF-UCL
Protein autophosphorylationManual Assertion Based On ExperimentIBA:GO_Central
Response to cytokineManual Assertion Based On ExperimentIDA:UniProtKB
Response to lipopolysaccharideISS:UniProtKB
Signal transductionManual Assertion Based On ExperimentTAS:ProtInc
Toll-like receptor signaling pathwayISS:UniProtKB
Vascular endothelial growth factor receptor signaling pathwayTAS:Reactome

Cellular Location

Nucleus
Cytoplasm
Predominantly located in the nucleus, when activated it translocates to the cytoplasm.

Involvement in disease

Macular dystrophy, patterned, 3 (MDPT3):
A form of retinal patterned dystrophy, characterized by retinal pigment epithelium and Bruch's membrane changes resembling a 'dry desert land'. It begins around the age of 30 and progresses to retinitis pigmentosa. MDPT3 inheritance is autosomal dominant.

PTM

Phosphorylated and activated by MAPK1/ERK2 and MAPK3/ERK1. Phosphorylated and activated by MAP kinase p38-alpha/MAPK14 at Thr-201, Ser-251 and Thr-313 (By similarity).