Pregnancy-specific beta-1-glycoprotein 2 (PSG2)

Pregnancy-specific beta-1-glycoprotein 2 (PSG2) is a secreted, glycosylated protein produced by placental trophoblasts and released into the maternal circulation, mainly during pregnancy[1][2][3][5]. It is a member of the pregnancy-specific glycoprotein (PSG) family, a subgroup within the carcinoembryonic antigen (CEA) gene family, itself part of the immunoglobulin superfamily[2][3][4][5]. PSG2, like other PSGs, features an N-terminal Ig variable-like domain and multiple immunoglobulin constant-like A/B domains. Most PSGs, including PSG2, contain an Arg-Gly-Asp (RGD) motif that mediates interactions with integrins and may function as a cell adhesion recognition signal[1][2][3][5]. The PSGs play key roles in the maternal-fetal interface, believed to modulate the maternal immune system and support successful pregnancy[4], although the specific functions of PSG2 remain less clearly defined in comparison to the family as a whole[2][4]. Family-wide, abnormal levels of PSGs are associated with pregnancy complications, but PSG2 is not a recognized therapeutic target and has no established drug interactions[4]. Special notes: - PSG2 is not considered a direct therapeutic target (e.g., as a receptor, enzyme, transporter) but rather a biomarker/component of a broader glycoprotein family important in pregnancy[1][2][3][4][5]. - There is confusion in the literature and databases between PSG2, PSG1, and generic "CEA," but PSG2 refers specifically to "pregnancy-specific beta-1-glycoprotein 2" as encoded by the PSG2 gene (NCBI Gene ID: 5670)[3]. - Some sources list "PSG1" and "CEA" as aliases, but these are more appropriately applied to the family or other members, contributing to ambiguity; the canonical identity is "Pregnancy-specific beta-1-glycoprotein 2 (PSG2)."

Other names

PSBG2PSG1Pregnancy-specific glycoprotein 2PS-beta-EPS-beta-G-2CEACarcinoembryonic antigen SG8

Not therapeutically targeted; any biological effects inferred from family properties (adhesion, immune modulation)