A sodium and potassium-stimulated adenosine triphosphatase from cardiac tissues—III

Schwartz, Arnold; Laseter, Arline H.

doi:10.1016/0006-2952(64)90035-8

Cited by 10 publications

(1 citation statement)

References 36 publications

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“…A membrane-bound ATPasO has been implicated in the active transport of (Na + + K +) in a number of cells and organs, e.g., crab nerves (9, 10), mammalian erythrocytes (11,12), kidney (13)(14)(15)(16)(17), brain (14,(18)(19)(20)(21), muscle (22,23), and many others (24)(25)(26)(27)(28)(29)(30)(31)(32). The implication is based on the finding that cation transport and membrane ATPase (sometimes referred to as "transport ATPase") have a number of features in common which have been discussed in detail by Skou (9,10), Post et al (l 1), and Dunham and Glynn (12).…”

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confidence: 99%

Adenosine Triphosphatase Localization in Amphibian Epidermis

Farquhar

Palade

1966

The Journal of Cell Biology

199

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The localization of ATPasO activity has been studied by light and electron microscopy in the epidermis of Rana pipiens, Rana catesbiana, and Bufo marinus. The reaction was carried out on skin (glutaraldehyde-fixed or fresh) sectioned with or without freezing. Best results were obtained with nonfrozen sections of fixed tissue. The incubation mixture was either a Wachstein-Meisel medium, or a modification which approximates assay systems used in biochemical studies of transport ATPases. The reaction product was found localized in contact with the outer leaflet of all cell membranes facing the labyrinth of intercellular spaces of the epidermis. It was absent from: (a) membrane areas involved in cell junctions (desmosomes, zonulae and maculae occludentes); (b) cell membranes facing the external medium (i.e., those on the distal aspect of the ultimate cell layer in s. corneum); (c) cell membranes facing the dermis (those on the proximal aspect of cells in s. germinativum). In the presence of (Na + + K +) the localization did not change, but the reaction was not appreciably activated. A similar though less intense reaction was obtained with ITP, but not with ADP, AMP, and GP as substrates. The results are discussed in relation to available data on transport ATPases in general, and on the morphology and physiology of amphibian skin in particular. Assuming that the ATPase studied is related to transport ATPase, the findings suggest a series of modifications to the frog skin model proposed by Koefoed-Johnsen and Ussing. The salient feature of this modified model is the localization of the Na + pump along all cell membranes facing the intercellular spaces of the epidermis.The inward transport of Na + across the frog skin is an active process (1, 2) inhibited by cardiac glycosides (3, 4) and dependent on energy provided by oxidative metabolism (5, 6), presumably oxidative phosphorylation (7). The transport mechanism, usually referred to as "the Na + I The abbreviations used in this paper are: ATPase, adenosine triphosphatase; ATP, adenosine triphosphate; ADP, adenosine diphosphate; AMP, adenosine monophosphate, or 5'-adenylic acid; GP, Na fl glycerophosphate; ITP, inosine triphosphate; (Na + + K+), Na + and K + present and acting (or being transported) concomitantly; s., stratum; Tris, tris (hydroxymethyl) aminomethane.pump," has been tentatively localized by KoefoedJohnsen and Ussing (8) on an "inward facing membrane" which they assume to be the cell membrane on the basal aspect of the stratum germinativum (s. basale) of the epidermis.

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