Inhibitor of the serine/threonine-protein kinase PAK4. Acts by binding PAK4 in a substrate-like manner, inhibiting the protein kinase activity. Interacts with PAK4 (PubMed:26607847). The Inka box (also named iBox or inca box) binds and inhibits PAK4 by binding a substrate-like manner. Belongs to the INKA family. Extended N-terminus. Extended N-terminus.