This domain is found in eukaryotes, and is approximately 220 amino acids in length. It is found in association with , . It is found is the middle region of SBF1 and SBF2, members of the myotubularin family. Myotubularin-related proteins have been suggested to work in phosphoinositide-mediated signalling events that may also convey control of myelination. Mutations of SBF2 are implicated in Charcot-Marie-Tooth disease []. SBF2 is a guanine nucleotide exchange factor (GEF) which activates RAB21 and possibly RAB28 [, ].
