Alternative titles; symbols
HGNC Approved Gene Symbol: LY86
Cytogenetic location: 6p25.1 Genomic coordinates (GRCh38): 6:6,588,720-6,654,982 (from NCBI)
The leucine-rich repeat (LRR) is a protein motif implicated in protein-protein interactions, and many proteins bearing this motif have a role in defense against pathogens. RP105 (LY64; 602226) is an LRR-bearing molecule that transmits an activation signal leading to massive B-cell proliferation as well as resistance against apoptosis. Md1 is a mouse secretory molecule tethered to the cell surface by Rp105. By searching an EST database with mouse Md1, Miura et al. (1998) identified a cDNA encoding MD1 from human fetal liver and spleen. The deduced MD1 protein contains 162 amino acids, shares 66% amino acid identity with mouse Md1, and has a predicted 19-amino acid signal peptide and 2 N-glycosylation sites. Six of 7 cysteine residues in human MD1 are conserved in mouse and chicken Md1. Northern blot analysis detected a 1.0-kb MD1 transcript in B-cell lines and the U937 monocyte line, but no expression was detected in 2 T-cell lines or in the K562 erythroleukemia line. Western blot and flow cytometry analysis demonstrated that expression of MD1, an approximately 25-kD protein, enhances surface expression of RP105. The authors found that MD1 is also expressed on the surface despite its lack of a transmembrane region.
Miura, Y., Shimazu, R., Miyake, K., Akashi, S., Ogata, H., Yamashita, Y., Narisawa, Y., Kimoto, M. RP105 is associated with MD-1 and transmits an activation signal in human B cells. Blood 92: 2815-2822, 1998. [PubMed: 9763566]