In vivo phosphorylation of the Na,K-ATPase alpha subunit in sciatic nerves of control and diabetic rats: effects of protein kinase modulators.

Abstract

The phosphorylation state of the Na,KATPase a subunit has been exaied in -uP-abee sciatic nerves of control and eptozo-treated dbetic rats. Intact nerves were c d with protein kiause (PK)

Effects of protein kinase C modulators on Na+/K+ adenosine triphosphatase activity and phosphorylation in aortae from rats with cirrhosis

“…Phosphorylation of the Na ϩ /K ϩ ATPase ␣-subunit has been shown to be a mechanism by which PKC exerts tonic control of Na ϩ /K ϩ ATPase activity in SMC and certain nonvascular cells. 3,8 Thus, a cirrhosisinduced reduction in PKC-dependent ␣-subunit phosphorylation may explain the decrease in Na ϩ /K ϩ ATPase activity in cirrhotic aortae.…”

“…25,26 In the fifth set of experiments, membrane potentials were measured before and during exposure to staurosporine (a PKC inhibitor, 10 Ϫ7 mol/L). 8,27 In the sixth set of experiments, membrane potentials were measured before and during exposure to the phorbol ester, phorbol 12,13-dibutyrate (PDBU) (a PKC activator, 10 Ϫ5 mol/L). 27 In the seventh set of experiments, the membrane potential response to ouabain was measured in aortae pretreated with staurosporine.…”

“…3,4 In addition, the ␣-subunit has been shown to be phosphorylated by protein kinase C (PKC) in subcellular fractions and intact nonvascular cells. [3][4][5][6][7][8] Moreover, PKCinduced phosphorylation regulates Na ϩ /K ϩ ATPase activity. 3 Na ϩ /K ϩ ATPase plays a role in maintenance of the cellular ionic milieu and membrane potential, and thus vascular tone.…”

Dissection of Metabolic, Vascular, and Nerve Conduction Interrelationships in Experimental Diabetic Neuropathy by Cyclooxygenase Inhibition and Acetyl-l-Carnitine Administration

“…Our finding, a reduction in nerve Na,K-ATPase activity induced by selective COX-2 inhibition in both ND and STZ-D rats, confirms the importance of COX-2 products in the maintenance of Na,K-ATPase activity. In addition to regulation through a cAMP-dependent protein kinase pathway (75,76), decreased Na,K-ATPase activity may reflect a COX inhibitor-exacerbated nerve energy deficit (77), secondary to disruption of mitochondrial function. The ability of ALC to ameliorate deficits in Na,K-ATPase activity despite potent COX inhibition is again consistent with a direct mitochondrial action (33)(34)(35)71) or possibly an effect mediated via COX-independent production of PGE 1 (78) or reduction in oxidative stress (79,80).…”

Apoptotic insults impair Na+, K+-ATPase activity as a mechanism of neuronal death mediated by concurrent ATP deficiency and oxidant stress

“…Phosphorylation state of the Na + , K + -pump in cells undergoing apoptosis Phosphorylation is a primary regulatory mechanism for activities of the Na + , K + -pump (Borghini et al, 1994;Feraille et al, 1997;Feschenko et al, 1997). To understand whether the reduced ATP level might affect the phosphorylation state of the Na + , K + -pump, its phosphorylation status was assessed using the antibody (anti-pan) recognizing serine, threonine, and tyrosine phosphorylated proteins, and the antibody against the pump α3 subunit that is commonly and abundantly expressed in brain neurons (Juhaszova and Blaustein, 1997;Habiba et al, 2000).…”