CFD

Complement factor D (CFD), also known as ADIPSIN, is a member of the S1, or chymotrypsin, family of serine peptidases. CFD plays an essential role in the activation of the alternative complement pathway. And it is expressed in a great number of tissues and cell types, however, the main source of plasma CFD in humans is derived from adipose tissue, in which it is secreted by both mature adipocytes and macrophages.
Similar to other secreted serine proteases, the N-terminal signal peptide of CFD is initially cleaved in the secretory pathway, producing an inactive zymogen, proCFD. Its subsequent maturation mainly can classify in two ways. Firstly, the five to six amino acid N-terminal activation domains in humans are quickly cleaved, either via the secretary pathway or soon after its release into plasma, generating 99% of plasma CFD in the CFD rather than proCFD form. Secondly, activation is considered to occur after CFD generation as a result of a conformational change which occurs when it binds C3bB, a complex of factor B, magnesium ions, and complement component 3b (C3b). Then, CFD becomes transiently active and enables to cleave factor B within this complex into Ba and Bb fragments. Additionally, CFD is found to express on pancreatic cancer and renal cancer cells.

Gene ID: 1675
UniProt ID: P00746