Alternative titles; symbols
HGNC Approved Gene Symbol: MMD
Cytogenetic location: 17q22 Genomic coordinates (GRCh38) : 17:55,392,622-55,421,835 (from NCBI)
Using differential display to identify genes that were induced during differentiation of monocytes into macrophages, Rehli et al. (1995) isolated a partial cDNA representing a transcript that was present in macrophages but not monocytes. The corresponding gene was named MMD. The authors isolated a full-length macrophage MMD cDNA encoding a deduced 238-amino acid protein containing 7 predicted transmembrane domains; however, the MMD protein has very low sequence similarity to members of the G protein-coupled receptor family and lacks many characteristics of this family. MMD has potential phosphorylation sites, N-myristoylation sites, and an N-glycosylation site. Northern blot analysis detected a 2.8-kb MMD transcript in macrophages, myeloid cell lines, lymphocytes, a hepatocellular carcinoma cell line, a colon carcinoma cell line, and placenta. MMD expression was not found in blood monocytes, skin fibroblasts, a ceratinocyte cell line, or a melanoma cell line.
By searching databases for sequences encoding a 7-transmembrane domain similar to those of ADIPOR1 (607945) and ADIPOR2 (607946), Tang et al. (2005) identified MMD, which they called PAQR11. The deduced 238-amino acid protein shares significant similarity with ADIPOR1 and ADIPOR2 only in the central 7-transmembrane domain. Database analysis revealed a mouse ortholog, which shares 99% amino acid identity with human PAQR11. RT-PCR analysis detected robust PAQR11 expression in all 20 tissues examined, with highest expression in adipose, followed by lung, colon, lymph node, skeletal muscle, kidney, brain, testis, bladder, prostate, breast, and skin.
Tang et al. (2005) determined that the MMD gene contains 7 coding exons.
By genomic sequence analysis, Tang et al. (2005) mapped the MMD gene to chromosome 17q22.
Rehli, M., Krause, S. W., Schwarzfischer, L., Kreutz, M., Andreesen, R. Molecular cloning of a novel macrophage maturation-associated transcript encoding a protein with several potential transmembrane domains. Biochem. Biophys. Res. Commun. 217: 661-667, 1995. [PubMed: 7503749] [Full Text: https://doi.org/10.1006/bbrc.1995.2825]
Tang, Y. T., Hu, T., Arterburn, M., Boyle, B., Bright, J. M., Emtage, P. C., Funk, W. D. PAQR proteins: a novel membrane receptor family defined by an ancient 7-transmembrane pass motif. J. Molec. Evol. 61: 372-380, 2005. [PubMed: 16044242] [Full Text: https://doi.org/10.1007/s00239-004-0375-2]