Membrane-spanning 4A
Membrane-spanning 4A genes are members of the CD20-like family. The MS4A genes are usually organized in a single genomic clusters in mammals, suggestive of gene duplication events.{{cite journal |vauthors=Liang Y, Buckley TR, Tu L, Langdon SD, Tedder TF |title=Structural organization of the human MS4A gene cluster on Chromosome 11q12 |journal=Immunogenetics |volume=53 |issue=5 |pages=357–68 |date=July 2001 |pmid=11486273 |doi= 10.1007/s002510100339|s2cid=21846867 }} MS4A genes encode a class of four-transmembrane spanning proteins. MS4A genes have been described to act as a specific kind of olfactory receptor in the necklace olfactory sensory neurons in mice (Mus musculus).Greer PL, Bear DM, Lassance JM, Bloom ML, Tsukahara T, Pashkovski SL, Masuda FK, Nowlan AC, Kirchner R, Hoekstra HE, et al. 2016. A family of non-GPCR chemosensors defines an alternative logic for mammalian olfaction. Cell. 165:1734–1748. [https://www.cell.com/cell/fulltext/S0092-8674(16)30549-9?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0092867416305499%3Fshowall%3Dtrue doi: 10.1016/j.cell.2016.05.001].
In human (Homo sapiens) the members of this family include: