Reagan J D
Sandoz Agro Inc., Palo Alto, CA 94304, USA.
Insect Biochem Mol Biol. 1995 Sep;25(8):875-80. doi: 10.1016/0965-1748(95)00049-2.
Fluid secretion in insects is controlled, in part, by diuretic hormones which bind to receptors on the surface of Malpighian tubule cells, leading to an increase in intracellular cAMP. Recent evidence suggests that Na(+)-K(+)-2Cl- cotransporters may be involved, upon stimulus by diuretic hormones, in transport of ions from the hemolymph to the lumen of the Malpighian tubules. In this report, I describe the cloning of a putative bumetanide sensitive Na(+)-K(+)-2Cl- cotransporter from the Malpighian tubules of the tobacco hornworm, Manduca sexta. This Na(+)-K(+)-2Cl- cotransporter is a Malpighian tubule specific isoform by Northern blot analysis. The protein consists of 1060 amino acids, contains 12 putative membrane spanning regions, and is related to other Na(+)-(K+)-Cl- cotransporters that have been cloned from shark, flounder, rat, rabbit and mouse. This protein is the first Na(+)-K(+)-2Cl- cotransporter that has been identified in an invertebrate.
昆虫的液体分泌部分受利尿激素控制，这些激素与马氏管细胞表面的受体结合，导致细胞内cAMP增加。最近的证据表明，在利尿激素的刺激下，Na(+)-K(+)-2Cl-协同转运蛋白可能参与离子从血淋巴到马氏管管腔的运输。在本报告中，我描述了从烟草天蛾Manduca sexta的马氏管中克隆出一种假定的布美他尼敏感型Na(+)-K(+)-2Cl-协同转运蛋白。通过Northern印迹分析，这种Na(+)-K(+)-2Cl-协同转运蛋白是马氏管特异性同工型。该蛋白质由1060个氨基酸组成，含有12个假定的跨膜区域，并且与从鲨鱼、比目鱼、大鼠、兔子和小鼠中克隆出的其他Na(+)-(K+)-Cl-协同转运蛋白相关。这种蛋白质是在无脊椎动物中鉴定出的首个Na(+)-K(+)-2Cl-协同转运蛋白。
