Inka box actin regulator 2 (INKA2)

Inka box actin regulator 2 (INKA2) is a protein that functions mainly as a specific endogenous inhibitor of the serine/threonine-protein kinase PAK4, a member of the p21-activated kinase family[1][2]. INKA2 achieves this inhibition by binding directly to the catalytic domain of PAK4 through its conserved "iBox" domain, thereby suppressing the kinase activity of PAK4, particularly in neurons and tumor cells. INKA2 plays critical roles in modulating actin cytoskeleton organization, cell morphology, adhesion, and migration, and is essential for normal dendritic spine development in the brain[2]. It also inhibits Wnt/β-catenin signaling by preventing stabilizing phosphorylation of β-catenin, promoting its degradation—a process that has implications in tumor growth and metastasis. INKA2 has been identified as a p53-induced tumor suppressor candidate whose expression is reduced in several cancers, suggesting it acts as a growth and migration inhibitor in tumor biology[1]. Alterations in INKA2 expression or function may impact cancer biology, neural development, and actin-dependent cellular processes. Currently, no direct pharmacological inhibitors or activators of INKA2 are in clinical use, but its mechanism provides a molecular blueprint for the development of new, substrate-selective PAK4 inhibitors[1][2].

Other names

PAK4-inhibitor INKA2C1orf183FAM212BInca-rInduced in neural crest by AP2-alpha protein-related homologHInca-rprotein FAM212B

Inhibition of PAK4 kinase activity through direct binding via the iBox domain. Interference with actin polymerization by suppressing the PAK4–LIMK–Cofilin signaling cascade[2]. Inhibition of β-catenin phosphorylation, resulting in β-catenin degradation and suppression of Wnt/β-catenin pathway signaling[1].