Several viruses, including human papillomaviruses, depend on endosomal acidification for successful infection. Hence, the multisubunit enzyme vacuolar ATPase (V-ATPase), which is mainly responsible for endosome acidification in the cell, represents an attractive target for antiviral strategies. In the present study, we show that V-ATPase is required for human papillomavirus (HPV) infection and ...

Membrane-rich vesicle preparations of rabbit and bovine lenses were prepared in such a manner as to preserve ATPase activity. The lipid:protein ratio of these preparations was increased 22- to 33-fold with a 94% recovery of total phospholipid. Using this preparation, calcium stimulated ATPase was routinely determined in both individual lenses and in pooled specimens. The pattern of stimulation ...

Labelling the Ca(2+)-ATPase of skeletal-muscle sarcoplasmic reticulum with o-phthalaldehyde (OPA) results in loss of ATPase activity at a 1:1 molar ration of label to ATPase. The affinity of the ATPase for CA2+ is unaffected, as is the E1/E2 equilibrium constant. The rate of dissociation of Ca2+ from the Ca(2+)-bound ATPase is also unaffected and Mg2+ increases the rate of dissociation, as for ...

Marinobufagenin (MBG), an endogenous ligand of alpha-1 Na/K-ATPase, becomes elevated and contributes to hypertension in NaCl-loaded Dahl-S rats (DS). Protein kinase C (PKC) phosphorylates alpha-1 Na/K-ATPase and increases its MBG sensitivity. Cicletanine, an antihypertensive compound with PKC-inhibitory activity, reverses MBG-induced Na/K-ATPase inhibition and vasoconstriction. We hypothesized ...

The vacuolar H(+)-ATPase (V-ATPase) in type A kidney intercalated cells is a major contributor to acid excretion in the collecting duct. The mechanisms of V-ATPase-trafficking regulation in kidney intercalated cells have not been well-characterized. In developmentally related epididymal clear cells, we showed previously that PKA, acting downstream of soluble adenylyl cyclase (sAC), induces V-AT...

The tonoplast-bound ATPase of Hevea brasiliensis (caoutchouc tree) was solubilized with dichloromethan and purified 100-fold with two ammonium sulfate precipitation steps and a G-200 gel filtration step. The resulting ATPase activity eluted according to a molecular mass of approximately 200 kDa and chromatographed at an isoelectric pH of 5.3. Subunits of molecular mass 110 kDa, 68 kDa, 24 kDa a...

The hepatic microsomal Ca2+- and Mg2+-dependent ATPase phosphoenzyme intermediates were distinguished by using the chelators EGTA and CDTA (trans-cyclohexane-1,2-diamine-NNN'N'-tetra-acetic acid). The Ca2+-ATPase intermediate is a hydroxylamine-labile base-labile 125 000-Mr phosphoprotein. The Mg2+-ATPase intermediate is a hydroxylamine-stable base-stable 30 000-Mr phosphoprotein. This enzyme i...

Gastric acid secretion is mediated by the H/K-ATPase of parietal cells. Activation of acid secretion involves insertion of H/K-ATPase into the parietal cell plasmalemma, while its cessation is associated with reinternalization of the H/K-ATPase into an intracellular storage compartment. The cytoplasmic tail of the H/K-ATPase beta subunit includes a four residue sequence homologous to tyrosine-b...

Isolated human red blood cell membrane fragments (RBCMF) were found to take up Ca(++) in the presence of ATP.(1) This ATP-dependent Ca(++) uptake by RBCMF appears to be the manifestation of an active Ca(++) transport mechanism in the red cell membrane reported previously (Schatzmann, 1966; Lee and Shin, 1969). The influences of altering experimental conditions on Ca(++)-stimulated Mg(++) ATPase...

Development of epidermis creates stratified epithelium with different sets of ion-transporting enzymes in its layers. We have characterized expression of Na,K- and H,K-ATPase α and β subunits and FXYD isoforms in rat skin. Maturation of rat skin from newborn to adult is associated with an increase in FXYD4 and a decrease of Na,K-ATPase α1-isoform, ATP1B4 and FXYD6 transcripts. Na,K-ATPase of ra...