DentinSialophosphoprotein

Dentin sialophosphoprotein (DSPP) is a secreted extracellular matrix protein of dentin, encoded by the DSPP gene in humans. The DSPP gene maps to chromosome 4q22.3 and belongs to the secretory calcium-binding phosphoprotein (SCPP) family. The DSPP protein is synthesized as a single preprotein containing a signal peptide and proprotein region, which is proteolytically cleaved to yield two mature dentin components: dentin sialoprotein (DSP) and dentin phosphoprotein (DPP).

DPP is highly acidic and extensively phosphorylated, while DSP is a sialylated glycoprotein. Both products are incorporated into the dentin extracellular matrix and contribute to mineralization. The processing of DSPP and the relative abundance of DSP and DPP influence the properties of dentin, including its mineral density and structural organization.

Expression of DSPP occurs primarily in odontoblasts and dental pulp cells during dentinogenesis. The DPP portion is implicated in calcium binding and interaction with hydroxyapatite crystals, whereas DSP is thought to interact with collagen type I and help coordinate mineral deposition. The balance between DSP and DPP activities affects dentin quality and dentinogenesis.

Genetic mutations in DSPP are associated with dentinogenesis imperfecta types II and III and dentin dysplasia type II, conditions characterized by abnormal dentin structure, translucency, and radiographic anomalies. These mutations can disrupt DSPP processing, secretion, or function, leading to altered dentin formation.

DSPP continues to be a focus in studies of odontoblast differentiation, dentin formation, and dental tissue engineering, serving as a key marker and a functional component in dentin mineralization research.