Protein kinase C-related kinase family (PKN/PRK)

The Protein kinase C-related kinase (PKN/PRK) family, comprising PKN1, PKN2, and PKN3, represents a group of serine/threonine kinases that act as key effectors of Rho GTPases (UniProt P23443, Q16513). These enzymes are characterized by an N-terminal regulatory region containing three HR1 (homology region 1) domains that mediate binding to RhoA, RhoB, and RhoC, and a C-terminal catalytic domain belonging to the AGC kinase subfamily (PMID: 23835560). PKNs are involved in diverse cellular processes, including cytoskeletal reorganization, vesicle trafficking, cell cycle regulation, and apoptosis (PMID: 21151178). In a clinical context, PKN family members are implicated in various pathologies, most notably cancer, where PKN3 is recognized as a validated target in prostate and pancreatic malignancies due to its role in tumor cell invasion and metastasis (PMID: 18648665). While specific PKN inhibitors are largely in the research phase, several multi-kinase inhibitors like Midostaurin have demonstrated activity against PKN1 (DrugBank DB06595). Development of selective inhibitors remains a priority to mitigate off-target effects associated with the structural similarity between PKN isoforms and other AGC kinases. The family's involvement in Rho-mediated signaling makes it a significant focus for therapeutic intervention in metastatic disease and cardiovascular remodeling.

Other names

PKN familyPRK familyProtein kinase C-related kinasesRho-activated serine/threonine kinasesPKC-related kinases

Small molecule inhibitors typically act via ATP-competitive inhibition of the C-terminal kinase domain, while oligonucleotide-based therapies like Atu027 utilize RNA interference to silence gene expression of specific isoforms like PKN3 (PMID: 21151178, PMID: 18648665).