TULP3 encodes a member of the tubby gene family of bipartite transcription factors. Members of this family have been identified in plants, vertebrates, and invertebrates, and they share a conserved N-terminal transcription activation region and a conserved C-terminal DNA and phosphatidylinositol-phosphate binding region.

The encoded protein binds to phosphoinositides in the plasma membrane via its C-terminal region and probably functions as a membrane-bound transcription regulator that translocates to the nucleus in response to phosphoinositide hydrolysis, for instance, induced by G-protein-coupled-receptor signaling. It plays an important role in neuronal development and function. Two transcript variants encoding distinct isoforms have been identified for this gene.