INSECT NA+ K+-ATPASE

Na+/K+-ATPase (sodium/potassium pump) is a P-type ion-motive ATPase fo und in the plasma membranes of animal cels. In vertebrates, the functi ons of this enzyme in nerves, heart and kidney are well characterized and characteristics a defined by different isoforms. In contrast, desp ite different tissue distributions, insects possess a single isoform o f the a-subunit. A comparison of insect and vertebrate Na+/K+-ATPases reveals that although the mode of action and structure are very highly conserved, the specific roles of the enzyme in most tissues varies. H owever, the enzyme is essential for the function of nerve cells, and i n this respect Na+/K+-ATPase appears to be fundamental in metazoan evo lution. (C) 1998 Elsevier Science. All rights reserved.