Expression of functional (Na⁺ + K⁺)‐ATPase from cloned cDNAs

Abstract

Xenopus oocytes injected with s(-and /?-subunit-specific mRNAs derived from cloned Torpedo californica cDNAs. Both the mRNAs are required for the expression of functional (Na+ + K+)-ATPase.

The functional roles of disulfide bonds in the β‐subunit of (Na,K)ATPase as studied by site‐directed mutagenesis

“…Rabbit antisera raised against the a and/?-subunits puritied from the electric organ of II: californica (Na,K)ATPase were described previously [2]. Enzymes used for site-directed mutagenesis and in vitro transcription were purchased from TaKaRa, Nippon Gene and Toyobo.…”

“…Although the functional role of the B-subunit, which is glycosylated, is not yet fully understood, there is evidence that it is required for biogenesis of the enzyme [2,3]. The &ubunit stabilizes the nascent &-subunit in the endoplasmic reticulum [4][5][6] and is also thought to play a role in targeting the @-complex to the plasma membrane [7-lo].…”

The β-Subunits of Na+,K+-ATPase and Gastric H+,K+-ATPase Have a High Preference for Their Own α-Subunit and Affect the K+ Affinity of These Enzymes

“…This formation of a complex between ␣-and ␤-subunits is also essential for enzyme activity (7)(8)(9) and occurs before the subunits are transported from the endoplasmic reticulum to the plasma membrane (10). Lemas et al (11) showed that the carboxylterminal 161 amino acids of the Na ϩ ,K ϩ -ATPase ␣-subunit are sufficient for assembly with the ␤-subunit.…”

Expression and targeting to the plasma membrane of xClC-K, a chloride channel specifically expressed in distinct tubule segments of Xenopus laevis kidney

“…IgGs were purified from final bleed antiserum by Protein A-Sepharose chromatography [15]. Crude membranes were prepared as described in [16] for oocytes, as described in [17] for kidney and as described in [18] for other tissues and cultured cells. Protein content was assessed [19] and aliquots were stored at k80 mC.…”