Syntaxin Binding Protein 5 Like Protein (STXBP5L)

The Drosophila gene Lethal giant larvae (Lgl) regulates epithelial polarity, and when mutated leads to tumor formation. Using homology searches with the human Lgl homolog LLGL1 as query, Katoh and Katoh (2004) identified the cDNA KIAA1006, which contained a homologous open reading frame that the authors named LLGL4.

The LLGL4 gene encodes a protein of 1,186 amino acids that shares 95.8% and 68.4% amino acid identity with mouse Llgl4 and human LLGL3, respectively. LLGL4 mRNA is expressed in hippocampus, kidney, lung carcinoid, and germ cell tumors. Sequence comparisons of LGL family members identified 3 conserved domains. In addition to these domains, LLGL4 contains 5 WD40 repeats and a C-terminal syntaxin-binding (STXB) domain.