InterPro domain: IPR006876

This group of proteins have a conserved C-terminal region which is found in LMBR1 and in the lipocalin-1 receptor. LMBR1 was thought to play a role in preaxial polydactyly, but recent evidence now suggests this not to be the case [ 1 ]. Vertebrate members of this family may play a role in limb development [ 2 ]. Lysosomal cobalamin transport escort protein LMBD1 is a lysosomal membrane chaperone required to export cobalamin from lysosome to the cytosol, allowing its conversion to cofactors [ 3 , 4 ]. This protein showed homology to the lipocalin membrane receptor (LIMR) [ 5 ].

1. Disruption of a long-range cis-acting regulator for Shh causes preaxial polydactyly. Proc. Natl. Acad. Sci. U.S.A. 99, 7548-53
2. Acheiropodia is caused by a genomic deletion in C7orf2, the human orthologue of the Lmbr1 gene. Am. J. Hum. Genet. 68, 38-45
3. Identification of a putative lysosomal cobalamin exporter altered in the cblF defect of vitamin B12 metabolism. Nat. Genet. 41, 234-9
4. Purification and interaction analyses of two human lysosomal vitamin B12 transporters: LMBD1 and ABCD4. Mol. Membr. Biol. 31, 250-61
5. Molecular cloning of a novel lipocalin-1 interacting human cell membrane receptor using phage display. J. Biol. Chem. 276, 20206-12