P311, also known as C5orf13 (chromosome 5 open reading frame 13), D4S114, PTZ17 or PRO1873, is a 68 amino acid cytoplasmic protein involved in cellular differentiation, neural function and axonal regeneration. Found in the granular layer of the cerebellum, P311 is expressed at lower levels in hippocampus, olfactory bulb, kidney, liver and heart and when expressed ectopically, P311 augments giloma motility. P311 is enriched in mice within the superficial cortical layers and striatum at E20 and the germinal zones at E17. Known to interact with Filamin 1, P311 regulates retinoic-acid lipid-droplet biogenesis, induces myofibroblast ameboid migration and the differentiation of fibroblasts into myofibroblasts. Ser-59 phosphorylation decreases P311 stability; the gene encoding P311 maps to human chromosome 5q22.