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serine/threonine protein kinase N1; protease-activated kinase 1; PAK-1; protein kinase C-like 1; protein kinase C-like PKN; protein kinase PKN-alpha; protein-kinase C-related kinase 1; serine-threonine protein kinase N (PKN1, PKN, PRK1, PRKCL1)
Function:
- PKC-related serine/threonine protein kinase
- role in various processes such as
a) regulation of the intermediate filaments of the actin cytoskeleton
b) transcription regulation
- regulates the cytoskeletal network by phosphorylating proteins such as VIM & neurofilament proteins NEFH, NEFL & NEFM, leading to inhibition of their polymerization
- phosphorylates Ser-575, Ser-637 & Ser-669 of MAPT/Tau, lowering its ability to bind to microtubules, resulting in disruption of tubulin assembly
- acts as a key coactivator of androgen receptor (AR)-dependent transcription, by being recruited to AR target genes & specifically mediating phosphorylation of Thr-11 of histone H3 (H3T11ph), a specific tag for epigenetic transcriptional activation that promotes demethylation of histone H3 Lys-9 (H3K9me) by KDM4C/JMJD2C
- phosphorylates HDAC5, HDAC7 & HDAC9, leading to impair their import in the nucleus
- phosphorylates Thr-38 of PPP1R14A, Ser-159, Ser-163 & Ser-170 of MARCKS, & GFAP
- able to phosphorylate RPS6 in vitro
- kinase activity is activated upon binding to Rho proteins (RHOA, RHOB & RAC1). activated by lipids, particularly cardiolipin & to a lesser extent by other acidic phospholipids
- activated by caspase-3 (CASP3) cleavage during apoptosis
- two specific sites, Thr-774 (activation loop of the kinase domain) & Ser-916 (turn motif), need to be phosphorylated for its full activation
- autophosphorylated; preferably on serine
- activated by limited proteolysis with trypsin
- interacts with ZA20D3 (putative)
- interacts with ANDR
- interacts with PRKCB
- interacts (via REM 1 & REM 2 repeats) with RAC1
- interacts (via REM 1 repeat) with RHOA interacts with RHOB
- in case of infection, interacts with S typhimurium protein sspH1
Kinetic parameters:
- KM=20.6 uM for HDAC5
Structure:
- the C1 domain does not bind the diacylglycerol (DAG)
- belongs to the protein kinase superfamily, AGC Ser/Thr
- protein kinase family, PKC subfamily
- contains 1 AGC-kinase C-terminal domain
- contains 1 C2 domain
- contains 1 protein kinase domain
- contains 3 REM (Hr1) repeats
Compartment:
- cytoplasm, nucleus, endosome, cell membrane
- associates with chromatin (ligand-dependent)
- localization to endosomes is mediated via its interaction with RHOB
- association with the cell membrane is dependent on Ser-374 phosphorylation
Alternative splicing: named isoforms=3
Expression:
- found ubiquitously
- expressed in heart, brain, placenta, lung, skeletal muscle, kidney & pancreas
General
protease-activated kinase
Properties
SIZE: entity length = 942 aa
MW = 104 kD
COMPARTMENT: cytoplasm
cell nucleus
STATE: active state
MOTIF: acetylation site
SITE: N-TERMINUS
EFFECTOR-BOUND: acetyl
REM {34-110}
MOTIF: proteolytic site {108-109}
REM {123-209}
MOTIF: Ser phosphorylation site {S205}
REM {210-291}
C2 domain {325-461}
MOTIF: binding site
FOR-BINDING-OF: phospholipid
Ca+2-binding site
Thr phosphorylation site {T353}
Ser phosphorylation site {S374}
Ser phosphorylation site {S376}
proteolytic site {454-455}
Ser phosphorylation site {S533}
Ser phosphorylation site {S537}
proteolytic site {558-559}
MOTIF: Ser phosphorylation site {S559}
Ser phosphorylation site {S561}
Ser phosphorylation site {S562}
kinase domain
SITE: 615-874
MOTIF: ATP-binding site
NAME: ATP-binding site
SITE: 621-629
ATP-binding site
NAME: ATP-binding site
SITE: 644-644
aspartate residue {D740}
Thr phosphorylation site {T774}
Thr phosphorylation site {T778}
AGC-kinase C-terminal {875-942}
MOTIF: Thr phosphorylation site {T914}
Ser phosphorylation site {S916}
Database Correlations
OMIM 601032
UniProt Q16512
PFAM correlations
Entrez Gene 5585
Kegg hsa:5585
ENZYME 2.7.11.13
References
- UniProt :accession Q16512
- Kemp BE, Pearson RB.
Protein kinase recognition sequence motifs.
Trends Biochem Sci. 1990 Sep;15(9):342-6. Review.
PMID: 2238044