Shootin1 is a 631 amino acid protein that belongs to the shootin family. The shootin1 protein contains three coiled-coil domains, a proline-rich region and interacts with RUFY3. Shootin1 is involved in the generation of internal asymmetric signals required for neuronal polarization. The shootin1 protein acts upstream of PI3K (phosphoinositide 3-kinase), by being required for spatially localized PI3K activity. By accumulating asymmetrically in a single neurite before polarization, shootin1 leads to axon induction for polarization, additionally the absence of shootin1 from the nascent axon's siblings by competition prevents the formation of surplus axons. Existing as seven alternatively spliced isoforms, the shootin1 gene is conserved in chimpanzee, dog, mouse, rat, chicken and zebrafish, and maps to human chromosome 10q25.3.