Intestinal epithelial cell calcium transporter proteins (None standardized for the group; individual components have abbreviations (e.g., TRPV6, PMCA1b, NCX1).)

The primary intestinal epithelial cell transporter proteins responsible for active calcium absorption are **TRPV6**, an apical membrane Ca²⁺ channel mediating entry into enterocytes; **calbindin-D9k**, which shuttles Ca²⁺ across the cytoplasm; **PMCA1b**, a plasma membrane ATPase extruding Ca²⁺ at the basolateral side; and **NCX1**, a sodium/calcium exchanger also contributing to basolateral efflux. Additionally, certain tight junction claudins (*Cldn2*, *Cldn12*) facilitate paracellular passive movement under high luminal Ca²⁺ conditions. This system is tightly regulated by vitamin D hormone signaling at multiple steps—especially upregulating gene expression during low dietary intake—to maintain systemic mineral balance essential for bone health[1][2][3][4]. Defects or dysregulation can result in clinically significant disturbances such as osteoporosis or hypocalcemia.

Other names

Intestinal calcium transportersEpithelial calcium channelsCalcium absorption proteins

Drugs or hormones that modulate these targets typically: - Enhance or inhibit transcellular Ca²⁺ entry via TRPV6. - Regulate extrusion via PMCA1b or NCX1. - Modulate paracellular permeability by affecting claudin expression/function. Vitamin D increases transcription/expression of several key transporter genes including TRPV6 and calbindins[3].