Figure 4.

Mechanisms of claudin-10b function in the secretory portion of sweat glands and the acinar cells of salivary and lacrimal glands. During secretion, apical Cl^– channels and basolateral K⁺ channels are activated. Na⁺, 2 Cl^– and K⁺ enter the cell via the basolaterally expressed NKCC1 transporter. Cl^– is secreted into the lumen whereas Na⁺ and K⁺ leave the cell basolaterally. The secretion of Cl^– drives Na⁺ transport via the paracellular claudin-10b channel and transcellular water transport via aquaporins. An abrogation of the claudin-10b-mediated Na⁺ transport would result in a complete dysfunction of sweat, saliva and tear secretion.