Recombinant Human MCEMP1 Fc Chimera Protein, CF

MCEMP1 (mast cell‑expressed membrane protein-1), or C19orf59 in humans, is a 22 kDa mast cell specific type II transmembrane protein expressed in lung (1). Human MCEMP1 cDNA encodes 187 amino acids (aa) including an 85 aa N‑terminal cytoplasmic region, a 21 aa transmembrane domain, and an 81 aa C‑terminal extracellular domain (ECD, aa 107‑187) that includes one potential N-glycosylation site. One potential 204 aa splice variant contains a 22 aa substitution for the C‑terminal five amino acids. Within the ECD, human MCEMP1 shares only 36‑44% aa sequence identity with presumed mouse, rat, canine, porcine and bovine MCEMP1 orthologs (1). The 5’ flanking sequence of human MCEMP1 contains motifs for NF kappa B/Rel and NFAT, indicating that MCEMP1 expression may be enhanced by stimuli that also enhance cytokine production, such as allergic reactions or pathogens (2). In addition to lung mast cells, protein expression of MCEMP1 has been identified in cord blood-derived cultured mast cells, the mast cell leukemia cell line HMC-1, the acute monocytic leukemia cell line THP-1, and primary CD14⁺ monocytes and mast cells within or adjacent to lung tumors (1). It is not found on peripheral blood lymphocytes, lymphocytic cell lines, or epithelial cells (1).