Human TMEM219 Antibody

TMEM219 (Transmembrane protein 219; also IGFBP3 Receptor) is a 30-35 kDa member of the 2-transmembrane group of the Pfam-A family of polytopic molecules. It is widely expressed, and appears to be a cell-surface receptor for IGFBP3. Only free IGFBP3 will bind to TMEM219; when complexed to IGF-I, IGFBP3 is unable to recognize the TMEM219 molecule. Ligation of TMEM219 inhibits cell proliferation and induces caspase-8 mediated apoptosis. It is suggested that procaspase-8 is normally sequestered by TMEM219. Following IGFBP3 binding, procaspase-8 is activated and released from TMEM219, resulting in the downstream activation of executioner caspases. Human TMEM219 is a 240 amino acid (aa) 2-transmembrane protein. It contains an N-terminal 20 aa cytoplasmic region, a 21 aa TM domain, a 164 aa extracellular region (aa 41-204), a second 21 aa TM domain, and a C-terminal 15 aa cytoplasmic tail. Over aa 41-200, human TMEM219 shares 82% aa sequence identity with mouse TMEM219.