Brain Acid Soluble Protein 1 (BASP1), also known as NAP-22, is a transcriptional cosuppressor that belongs to the BASP1 family of proteins. Human BASP1 is 227 amino acids (aa) in length with a predicted molecular weight of approximately 23 kDa. It shares 72% and 70% aa sequence identity with the mouse and rat orthologs, respectively. BASP1 contains multiple residues that can undergo various posttranslational modifications including Gly2, which can be myristoylated, Lys79 and Lys84, which can be SUMOylated, and eight different phosphorylation sites. Additionally, BASP1 has one splice variant that shows a deletion of aa 88-141. BASP1 is expressed in neurons, renal podocytes and spermatids. It binds to the cytoplasmic side of the plasma membrane via its myristoylated adduct, and undergoes nuclear translocation when SUMOylated. BASP1 has also been shown to be associated with growth cone membranes in elongating axons and, thus, play a critical role in axon guidance, neuroregeneration, and synaptic plasticity.