Muscle LIM Protein is a Regeneration Associated Protein and promotes Axon Regeneration. MLP promotes Axon Regeneration

Muscle LIM Protein (MLP) has long been regarded as a muscle specific protein. Here, we report the induction of MLP expression in adult rat retinal ganglion cells (RGCs) upon axotomy and its correlation with the ability of these neurons to regenerate injured axons. Specific knockdown of MLP in RGCs compromised lens injury mediated axon regeneration, while overexpression facilitated optic nerve regeneration and regrowth of sensory neurons without affecting neuronal survival. Accumulation of MLP was found in the somas, including the nuclei and in the axonal growth cones, which were significantly enlarged by its overexpression. Only the protein fraction in the growth cones was relevant for axon extension in a F-actin dependent manner. Additional data suggest that MLP acts as an actin-cross-linker in neurons thereby facilitating filopodia formation and accelerating the motility of growth cones. Thus, MLP mediated effects on actin could become a novel therapeutic strategy for promoting nerve repair.