Scavenger receptor cysteine-rich family member with 4 domains (SSC4D)

Scavenger receptor cysteine-rich family member with 4 domains (SSC4D) is a soluble member of the SRCR superfamily, defined by four group B SRCR domains separated by proline, serine, and threonine-rich regions[1][2][3]. These domains feature eight regularly spaced cysteine residues critical for structure. SSC4D is mainly expressed by epithelial cells in the kidney, thyroid, lung, placenta, intestine, and liver, and also expressed by immune cells such as monocytes/macrophages and B cells[1][2][3]. Functionally, SSC4D acts as a broad-spectrum pattern recognition receptor, able to physically bind to multiple species of Gram-positive and Gram-negative bacteria and protozoan parasites—enhancing their opsonization and uptake by monocytes, indicating a role in bridging innate immune response with pathogen clearance[1][2][3]. Alternative splicing may yield different isoforms, but its main mature form is a glycosylated, soluble extracellular receptor[2]. There is currently no evidence for approved drugs targeting SSC4D, and little is known about any therapeutic risks or biomarker roles. Diseases linked to SSC4D include placental choriocarcinoma and Williams-Beuren syndrome, likely through its broader involvement in immune and placental functions[3]. Key references: [1][2][3].

Other names

Scavenger receptor cysteine-rich domain-containing group B proteinSRCRB4DSRCRB-S4DS4D-SRCRBFour scavenger receptor cysteine-rich domains-containing proteinScavenger receptor cysteine-rich protein SRCRB-S4DScavenger receptor cysteine rich family, 4 domains

Pattern recognition and opsonization of pathogens, enhancing phagocytosis by monocytes, facilitating innate immune clearance[1][2].