Cystic Fibrosis Transmembrane conductance Regulator (CFTR) anion channels are the regulated exit pathway in Cl- secretion by teleost salt secreting ionocytes of the gill and opercular epithelia of euryhaline teleosts. By confocal light immunocytochemistry using regular and phospho-antibodies directed against conserved sites, we found that killifish CFTR (kfCFTR) and the tyrosine kinase Focal Adhesion Kinase (FAK) phosphorylated at Y407 (FAKpY407) and FAKpY397 are colocalized at the apical membrane and in subjacent membrane vesicles of ionocytes. Hypotonic shock and the α-2 adrenergic agonist clonidine rapidly and reversibly inhibit Cl- secretion by isolated opercular epithelia, simultaneous with dephosphorylation of FAKpY407 and increased FAKpY397, located in the apical membrane of ionocytes in the opercular epithelium. FAKpY407 is re-phosphorylated at the apical membrane of ionocytes and Cl- secretion rapidly restored by hypertonic shock, detectable at 2 min., maximum at 5 min and still elevated at 30 min. In isolated opercular epithelia, the FAK phosphorylation inhibitor Y15 and p38MAP kinase inhibitor SB203580 significantly blunted the recovery of short-circuit current (Isc, equal to Cl- secretion rate) after hypertonic shock. The cSRC inhibitor saracatinib dephosphorylated FAKpY861 seen near tight junctions of pavement cells, and reduced the increase in epithelial resistance normally seen with clonidine inhibition of ion transport, while FAKpY397 was unaffected. The results show rapid osmosensitive responses in teleost fish ionocytes involve phosphorylation of CFTR by FAKpY407, an opposing role for FAKpY397 and a possible role for FAKpY861 in tight junction dynamics.

中文翻译：

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斑纹硬ost鱼眼底Fund的离子细胞中的黏着斑激酶和渗透反应。

囊性纤维化跨膜电导调节剂（CFTR）阴离子通道是由tele硬骨鱼tele的硬骨细胞分泌盐的离子细胞和硬脑膜硬骨膜的上皮上皮细胞在Cl-分泌中调节的出口途径。通过使用针对保守位点的常规抗体和磷酸化抗体的共聚焦光免疫细胞化学，我们发现在Y407（FAKpY407）和FAKpY397处磷酸化的幼鱼CFTR（kfCFTR）和酪氨酸激酶Focal Adhesion Kinase（FAK）共同定位在心尖膜和下方。离子细胞的膜囊泡。低渗性休克和α-2肾上腺素能激动剂可乐定可迅速且可逆地抑制离体的上皮细胞的Cl分泌，同时使FAKpY407的去磷酸化作用和FAKpY397的磷酸化作用增加，而FAKpY397位于上皮细胞的离子细胞的顶膜中。FAKpY407在离子细胞的顶膜处重新磷酸化，Cl-分泌通过高渗休克迅速恢复，在2分钟时可检测到，在5分钟时最大，在30分钟时仍升高。在孤立的眼睑上皮细胞中，FAK磷酸化抑制剂Y15和p38MAP激酶抑制剂SB203580明显阻碍了高渗性休克后短路电流（Isc，等于Cl分泌率）的恢复。cSRC抑制剂saracatinib使磷酸化的FAKpY861脱去，在路面细胞紧密连接附近，并减少了可乐定抑制离子传输，通常可以看到上皮抵抗力的增加，而FAKpY397则不受影响。结果表明，硬骨鱼离子细胞中的快速渗透敏感性反应涉及FAKpY407对CFTR的磷酸化作用，