Cloning and expression of a Na(+), K(+)-ATPase alpha-subunit from Taenia solium (TNaK1alpha)

The Na(+), K(+)-ATPase are membrane-associated enzymes that transport Na(+) and K(+) across the membrane generating chemical and electrical gradients, essential to maintain the resting potential for the excitation of myocytons and neurons and for transport of nutrients. The cDNA encoding a full-length isoform of Taenia solium Na(+), K(+)-ATPase alpha-subunit (TNaK1alpha) was isolated from a cysticercal cDNA library. TNaK1alpha has 1014 amino acids and a predicted molecular mass of 111,989Da. The protein displays strong sequence homology and conserved motifs typical of Na(+), K(+)-ATPase alpha-subunits. Northern and Southern hybridizations reveal a TNaK1alpha mRNA of about 3.7kb, which is encoded by a single gene. Polyclonal antibodies raised against a synthetic peptide corresponding to the NH(2)-terminal sequence of TNaK1alpha recognized a 100-kDa polypeptide in the membrane fraction of adult and larval stages of T. solium and other Taenia species. Immunolocalization studies using the same antibodies revealed that the TNaK1 is preferentially localized in muscle cells and protonephridial ducts, and in small quantities in the tegument of T. solium cysticerci.