CYBASC3 Activators

Cytochrome b561 family member A3 (CYB561A3), also known as duodenal cytochrome b (Dcytb), is a transmembrane protein that belongs to the cytochrome b561 family of proteins. These proteins are characterized by their heme-binding domains and their role in electron transfer across cellular membranes. CYB561A3 is specifically known for its function in the reduction of ferric to ferrous iron at the brush border of the duodenum, which is an essential step in dietary iron absorption.

CYB561A3 utilizes ascorbate (vitamin C) as an electron donor to reduce iron, which is then transported into the cell by divalent metal transporter 1 (DMT1). This process is vital for maintaining iron homeostasis in the body and blcoking conditions such as anemia. The protein is expressed on the apical surface of enterocytes in the duodenum, which is the primary site for iron absorption.The activity of CYB561A3 is tightly regulated by the body's iron needs, with expression levels responding to iron stores and demand. When iron levels are low, the body upregulates proteins like CYB561A3 to increase iron absorption. Conversely, when iron is abundant, the expression of CYB561A3 is reduced to blocking excess iron accumulation, which can be toxic.