Plays a major role in tight junction-specific obliteration of the intercellular space, through calcium-independent cell-adhesion activity. Involved in the regulation of paracellular epithelia permeability to ions in multiple organs. It acts as a paracellular ion channel probably forming permselective pores; isoform 1 appears to create pores preferentially permeable to cations and isoform 2 for anions. In sweat glands and in the thick ascending limb (TAL) of Henle's loop in kidney, it controls paracellular sodium permeability which is essential for proper sweat production and renal function. Can form homodimers both in trans (interaction between CLDN10 molecules in opposing membranes) and in cis (interaction between CLDN10 molecules within one membrane). Isoform 1, isoform 2 and isoform 4 localize in the cell membrane and at epithelial tight junctions, whereas isoform 3, isoform 5 and isoform 6 are detected in the endoplasmic reticulum. Strong expression detected in brain cortex and kidney and weak expression in lung and cecum. In kidney, detected in thick ascending limb (TAL) of Henle's loop and proximal convoluted tubule (PCT). Isoform 1 is widely expressed, with highest expression detected in brain cortex, kidney and lung. Isoform 2, isoform 3, isoform 4 and isoform 5 are only detected in kidney and uterus. In kidney, the expression of isoform 1 is highest in medulla, with transcripts being detected in medullary thick ascending limb of Henle's loop (mTAL) and outer and inner medullary collecting ducts, whereas isoform 2 (along with isoform 4) is more highly expressed in cortex, with transcripts being detected in PCT, mTAL and cortical collecting duct. Expressed in the inner ear where it is detected in organ of Corti, marginal cells of stria vascularis, Reissner's membrane and spiral limbus (at protein level) (PubMed:14698084). Expressed in salivary glands and skin (PubMed:28771254). Detected in developing kidney at 14 dpc, with levels increasing towards adulthood. Expressed during tooth development: at 12 dpc, detected in the thickening tooth epithelium, at 13.5 dpc in the lingual basal epithelium of the bud epithelium, at 14.5 dpc in lingual epithelium and between 18 dpc to postnatal day 1 in odontoblasts and stratum intermedium. The fourth transmembrane region (161-181), which is missing in isoform 3, isoform 5 and isoform 6, is necessary for integration into tight junctions. Conditional knockout in the thick ascending limb (TAL) of Henle's loop in kidney leads to hypocalcemia, hypermagnesemia, hyperphosphatemia and nephrocalcinosis. Produced by alternative splicing of isoform 2. Produced by alternative splicing of isoform 3. Belongs to the claudin family.