Subdomains are indicated as follows: CSRD, cysteine/serine-rich domain; TBD, tubulin-binding domain; GRD, GAP-related domain; Sec14/PH, Sec14-homologous domain and pleckstrin homology domain; NLS, nuclear localization sequence. Numbers above each subdomain indicate the positions of the corresponding amino acids within the 2818 amino acid length of the neurofibromin protein. The amino acid position of the TBD is not indicated, as this is an 80 amino acid region found within the N-terminal GRD domain.