The murine calcium-sensitive chloride channel (mCaCC) is widely expressed in secretory epithelia and in other select tissues

Abstract

The tissue and cellular expression pattern of a recently cloned murine calcium-sensitive chloride channel (mCaCC) was determined. In situ hybridization was performed on formalin-fixed, paraffin-embedded murine tissues using digoxigenin-labeled, single-stranded RNA probes. The data were substantiated with northern blot and reverse transcriptase-polymerase chain reaction analyses. All three assays consistently indicated strong expression in tissues with secretory or ion regulatory functions, such as mammary gland, respiratory and intestinal epithelia, gall bladder, pancreas, kidney, uterus, and epididymis. Additional mCaCC expression was observed in germinal centers of lymphatic tissues, in spermatids, and in keratinocytes of the skin, esophagus, and cornea. The results are in accordance with previous electrophysiological reports on calcium-activated chloride conductances in various murine exocrine secretory epithelia and suggest a role of mCaCC in transepithelial ion transport. However, expression in other than secretory tissues indicates a more complex function.

Correction of CFTR malfunction and stimulation of Ca2+-activated Cl− channels restore HCO3 − secretion in cystic fibrosis bile ductular cells

“…54 Stimulation of these receptors may promote anion transport both in biliary 18,21,22 and pancreatic 55 duct epithelial cells, at least transiently. 19,20 Interestingly, ATP stimulated HCO 3 Ϫ secretion only in the presence of elevated intracellular cAMP as previously shown. 18 In both control and CF cholangiocytes continuous presence of ATP (100 mol/L) alone had no stimulatory effect on the basal rate of HCO 3 Ϫ secretion (Figs.…”

“…In addition to cAMP-stimulated Cl Ϫ channels, Ca 2ϩ -activated Cl Ϫ conductances have also been described in both murine 19,20 and human biliary epithelial cells, 21,22 but their relationship to HCO 3 Ϫ secretion and their function in CFTR-deficient cells are unknown. We studied these relationships in both control and CFTR-deficient human bile duct cells.…”

Re-expression of Detachment-inducible Chloride Channel mCLCA5 Suppresses Growth of Metastatic Breast Cancer Cells

“…hCLCA2 belongs to a recently discovered family of proteins, currently comprising about a dozen members, that are widely expressed in mammals but apparently not beyond (19 -28). Various family members are found in epithelia, endothelia, and smooth muscle of multiple organs (21,24,25,27,28). CLCAs do not resemble any other known Cl Ϫ channel (i.e.…”

“…The family is deeply divergent, some members sharing as little as 36% identity, yet all share certain signatory features. The prototypical CLCA family member is a type I transmembrane protein about 900 amino acids in length with a proteolytic cleavage near amino acid 680 that results in products of 90 kDa and 30 -40 kDa that are found in close association on the exterior surface of the plasma membrane (19,24,26,28). Another common feature is a symmetrical multiple-cysteine motif, CX 12 CX 4 CX 4 CX 12 C, in the amino-terminal tail.…”

Molecular Cloning and Expression of Suppressor of Potassium Transport Defect 3 (SKD3) in Rat Testis.

“…I n a s t u d y o f p o t a s s i u m c h a n n e l s i n spermatocytes, in situ hybridization for the mRNA of slo3, a pH-sensitive potassium channel, showed that its expression was largely restricted to spermatocytes [19]. Other channels were also localized in sperm [20][21][22][23]. It is possible that SKD3 has effects on the opening of several potassium channels or the transcription of their mRNAs in Leydig and/or Sertoli cells.…”