UNC-13 has several mammalian homologues. The
UNC-13L-R structure is shown. This form is similar to the published
form of UNC-13 (Maruyama and Brenner, 1991). Additional N-terminal
regions, including a third C2 domain, were identified in cDNA library
screens (GenBank accession number M62830). C1 and C2 represent PKC
homology domains. Munc13-1, Munc13-2, and Munc13-3 (GenBank accession
numbers U24070, U24071, and U75261, respectively) are rat homologues of
C. elegans UNC-13 (Brose et al., 1995).
Hmunc13 (GenBank accession number AF020202) is a human homologue of
UNC-13 (Song et al., 1999). The UNC-13L region is 30%
identical to the N-terminal region of Munc13-1.