Serine/threonine-protein kinase VRK2
Function
Serine/threonine kinase that regulates several signal transduction pathways (PubMed:14645249, PubMed:16495336, PubMed:16704422, PubMed:17709393, PubMed:18286207, PubMed:18617507, PubMed:20679487). Isoform 1 modulates the stress response to hypoxia and cytokines, such as interleukin-1 beta (IL1B) and this is dependent on its interaction with MAPK8IP1, which assembles mitogen-activated protein kinase (MAPK) complexes (PubMed:17709393). Inhibition of signal transmission mediated by the assembly of MAPK8IP1-MAPK complexes reduces JNK phosphorylation and JUN-dependent transcription (PubMed:18286207). Phosphorylates 'Thr-18' of p53/TP53, histone H3, and may also phosphorylate MAPK8IP1 (PubMed:16704422). Phosphorylates BANF1 and disrupts its ability to bind DNA and reduces its binding to LEM domain-containing proteins (PubMed:16495336). Down-regulates the transactivation of transcription induced by ERBB2, HRAS, BRAF, and MEK1 (PubMed:20679487). Blocks the phosphorylation of ERK in response to ERBB2 and HRAS (PubMed:20679487). Can also phosphorylate the following substrates that are commonly used to establish in vitro kinase activity: casein, MBP and histone H2B, but it is not sure that this is physiologically relevant (PubMed:14645249).
Isoform 2
Phosphorylates 'Thr-18' of p53/TP53, as well as histone H3. Reduces p53/TP53 ubiquitination by MDM2, promotes p53/TP53 acetylation by EP300 and thereby increases p53/TP53 stability and activity.
Post-translational modifications
Isoform 1
Autophosphorylated.
Isoform 2
Autophosphorylated.
Sequence Similarities
Belongs to the protein kinase superfamily. CK1 Ser/Thr protein kinase family. VRK subfamily.
Tissue Specificity
Isoform 1 and isoform 2 are expressed in various tumor cell lines. Expression of isoform 1 inversely correlates with ERBB2 in breast carcinomas (at protein level). Widely expressed. Highly expressed in fetal liver, skeletal muscle, pancreas, heart, peripheral blood leukocytes and testis.
Cellular localization
- Isoform 1
- Cytoplasm
- Endoplasmic reticulum membrane
- Single-pass type IV membrane protein
- Mitochondrion membrane
- Single-pass type IV membrane protein
- Nucleus envelope
- Isoform 2
- Cytoplasm
- Nucleus
Alternative names
Serine/threonine-protein kinase VRK2, Vaccinia-related kinase 2, VRK2