Subunit assembly and functional maturation of Na,K-ATPase

Changes in gill H+-ATPase and Na+/K+-ATPase expression and activity during freshwater acclimation of Atlantic salmon (Salmo salar)

“…These two subunits assemble in a 1:1 ratio creating an  heterodimer. The Na + /K + -ATPase -subunit is thus required for proper function of the Na + /K + -ATPase, playing a role in maturation, delivery and insertion of the  heterodimer into the plasma membrane (Bystriansky and Kaplan, 2007), and potentially influencing the catalytic activity of the enzyme (Geering, 2005). As increased Na + /K + -ATPase protein abundance requires both an -and a -subunit, any increase in -subunit protein would require an equivalent increase in -subunit synthesis.…”

Multiplicity of expression of Na+,K+–ATPaseα-subunit isoforms in the gill of Atlantic salmon (Salmo salar): cellular localisation and absolute quantification in response to salinity change

“…Whereas the α-subunit is the catalytic component determining the transport kinetics of the Na + ,K + -ATPase, the β-subunit is essential for stabilisation of the α-subunit, membrane targeting, structural and functional maturation of the pump (Ackerman and Geering, 1990;Geering, 1990;Scheiner-Bobis, 2002). Compared with the α-subunit, very few studies have addressed the expression and regulation of the β-subunit in teleosts [Danio rerio (Appel et al, 1996); Anguilla anguilla (Cutler et al, 2000); Sparus sarba (Deane and Woo, 2005); S. salar (Nilsen et al, 2007)].…”

The P-type ATPase CATP-1 is a novel regulator ofC. elegansdevelopmental timing that acts independently of its predicted pump function

“…Na + /K + and H + /K + Ptype ATPases have been extensively characterized in vertebrates (Jorgensen et al, 2003;Kaplan, 2002 (Moller et al, 1996). The ␣-subunits of both enzymes probably incorporate all of the structural features required for enzymatic activity, whereas the ␤-subunits are necessary to ensure both the structural integrity of the dimeric protein complex as well as its proper delivery to the plasma membrane (Geering, 1990;Gottardi and Caplan, 1993). Type IIC ATPases have been subdivided into three subclasses based on their ionic specificity, pharmacological properties and expression profile: (1) (Caplan, 1997;Jaisser and Beggah, 1999;Kuhlbrandt, 2004) (Fig.…”