HBV Surface Antigen-preS2 Protein

Activin receptor type-2A (ACVR2A) is also known as Activin receptor type IIA, ACTR-IIA, ACTRIIA and ACVR2, which is single-pass type I membrane protein. They function through heteromeric complexes of type I and type II serine/threonine kinase receptors. Dimeric ligands bind to a type II receptor, such as Activin Receptor IIA (ActRIIA), which then associates with a type I receptor to initiate signal transduction. On ligand binding, ACVR2A forms a receptor complex consisting of two type II and two type I transmembrane serine/threonine kinases. Type II receptors phosphorylate and activate type I receptors which autophosphorylate, then bind and activate SMAD transcriptional regulators. ACVR2A is a receptor for activin A, activin B and inhibin A as well. Mature human ActRIIA is a 70 kDa glycoprotein that consists of a 116 amino acid (aa) extracellular domain (ECD), a 26 aa transmembrane segment, and a 352 aa cytoplasmic region that includes the kinase domain and a PDZ-binding motif. Activin proteins are involved in a wide range of biological processes including mesoderm induction, neural cell differentiation, bone remodeling, hematopoiesis, the regulation of reproductive physiology, inflammation, and carcinogenesis.Hepatitis B surface antigen S2 (HBV Surface Antigen-preS2) is the smallest unit of transcriptional activator encoded by the surface gene of hepatitis B virus (HBV). It can be used as an auxiliary diagnostic reagent for hepatitis B virus infection. It exists in more than 1/3 of HBV integration units, and HBV integration units are an important factor in inducing liver cancer (HCC). HBV Surface Antigen-preS2 is also an effective regulator of apoptosis induced by tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). It is involved in promoting hepatocyte apoptosis induced by TRAIL, thereby increasing the risk of malignant transformation of human hepatocellular carcinoma cell line (HepG2).