Inflammatory response in gastrointestinal cancers: Overview of six transmembrane epithelial antigens of the prostate in pathophysiology and clinical implications

Figure 1 Schematic representation of protein structure of six transmembrane epithelial antigens of the prostate. Six transmembrane epithelial antigens of the prostate (STEAPs) are similar in structure, with six transmembrane domains, an intracellular C-terminus, and an intracellular N-terminus containing the intracellular heme group, while STEAP1 Lacks FNO-like domain to perform intrinsic metal reductase activity. STEAP2-4 are involved in cell proliferation, tumor progression, and intercellular communication through their metalloreductase activity. FNO: F420H2:NADP+ oxidoreductase.

Figure 2 Molecular structure diagram of six transmembrane epithelial antigens of the prostate 1-4. The six transmembrane epithelial antigens of the prostate (STEAP) family is composed of a group of cell surface transmembrane proteins with six potential transmembrane domains, one intracellular amino terminus, and a carboxyl terminus that exert physiological functions by acting as oxidoreductases. STEAP1-4 consist of 339, 490, 488, and 459 amino acid residues, respectively. Except STEAP1, the N-terminus of the STEAP2-4 proteins contains the F420H2:NADP+ oxidoreductase binding protein domain. TM: Transmembrane domain; STEAP: Six transmembrane epithelial antigen of the prostate.