AGC kinase homology requires and enables co-targeting for CNS regeneration

Axon regrowth in the central nervous system (CNS) is constrained by robust regulatory networks. Here we show that optimal neurite outgrowth in rodent and human CNS neurons is achieved by co-inhibition of kinases across four closely related clades within the protein kinase A, G, and C (AGC) family. The kinases derive from ancestral regulators of cytoskeletal dynamics, resource allocation, and polarized cell growth. Their shared domain architecture makes polypharmacology (co-engagement by a single small molecule) feasible. Phenotype-guided optimization of a tool compound with established efficacy in mouse spinal cord injury models yielded TMP-316, a drug candidate engaging these AGC kinases with selectivity against the broader kinome. A single intrathecal dose of TMP-316 produced sustained motor recovery in a rat cervical hemicontusion model. These findings reveal conditions under which polypharmacology is simultaneously required and enabled by shared evolutionary origins, illuminating a therapeutic discovery principle for pathologies governed by functionally overlapping targets.