Human IGSF3 Alexa Fluor™ Plus 680‑conjugated Antibody

IGSF3 (Immunoglobulin superfamily member 3; also EWI-3) is a 133 kDa (predicted) member of the EWI subfamily of the Ig-Superfamily of molecules. It is reported to be widely expressed, with concentration in placenta and lung. Human IGSF3 an 1194 amino acid (aa) type I transmembrane protein that contains a 19 aa signal sequence followed by an 1175 aa mature region (aa 20-1194) (SwissProt # O75054). The molecule's extracellular region is 1105 aa in length (aa 20-1124), and contains eight C2-type Ig-like domains (aa 22-1097). This region also possesses at least two utilized phosphorylation sites at Thr617and Ser625, plus an EWI motif in the second Ig-like domain. IGSF3 likely exists as a disulfide-linked homodimer. There are two potential isoform variants. One contains a 20 aa insertion after Pro406, while another shows the same insert coupled to a premature truncation after Pro833. GenBank Accession # AAI10652 is identical to the SwissProt sequence above save for a double Glu substitution for Asp1020 in the eighth Ig-like domain. Over aa 20‑1125, human IGSF3 shares 92% aa identity with mouse IGSF3.