SIRPa protein

Patent Pending Signal regulatory protein α (SIRP α) is regulatory membrane glycoprotein from SIRP family expressed mainly by myeloid cells and also by stem cells or neurons. SIRP α acts as inhibitory receptor and interacts with a broadly expressed transmembrane protein CD47 called also don´t eat me signal. This interaction negatively controls effector function of innate immune cells such as host cell phagocytosis. This is analogous to the self signals provided by MHC class I molecules to NK cells via Ig-like or Ly49 receptors.