The protein encoded by this gene is found in the cytoplasm of quiescent cells but translocates to the nucleolus in proliferating cells. The encoded protein interacts with survival motor neuron protein (SMN1) to enhance pre-mRNA splicing and to induce neuronal differentiation and axonal growth. Defects in this gene or the SMN1 gene can cause spinal muscular atrophy. Two transcript variants encoding different isoforms have been found for this gene. Acts as a signaling molecule that communicates proliferative growth signals from the cytoplasm to the nucleus. Plays a role for the localization and accumulation of the survival motor neuron protein SMN1 in sub-nuclear bodies, including gems and Cajal bodies. Induces neuron differentiation and stimulates axonal growth and formation of growth cone in spinal cord motor neurons. Plays a role in the splicing of cellular pre-mRNAs. May be involved in H2O2-induced neuronal cell death.