Cyclic AMP—Dependent Reversible Phosphorylation of Renal Medullary Plasma Membrane Protein

Cellular Action of Antidiuretic Hormone in Mice with Inherited Vasopressin-Resistant Urinary Concentrating Defects

“…Cyclic AMP phosphodiesterase was measured by the method described by Thompson and Appleman (19) Cyclic AMP-dependent protein kinase was assayed by the method employed in our previous study (11), with some modifications. The protein substrate used was either endogenous, i.e., proteins of the cytosol contained in the enzyme preparation, or exogenous, in the form of 100 ,ug of mixed calf thymus histones (Schwartz/Mann Div., Becton, Dickinson & Co., Orangeburg, N.…”

“…Y. ); otherwise the incubation mixture was as described previously (11). The enzyme reaction was stopped by addition of 1 ml of 10% trichloroacetic acid (TCA).…”

Effects of Colchicine and Vinblastine on the Cellular Action of Vasopressin in Mammalian Kidney A POSSIBLE ROLE OF MICROTUBULES

“…The mechanism by which cyclic AMP formed under the influence of vasopressin increases water permeability of collecting ducts remains unknown. Still hypothetical is the idea that cyclic AMP acts on the lumenal plasma membrane through its influence on protein phosphorylation (3)(4)(5). Taylor, Mamelak, Raven, and Maffly (6) found that some drugs known to disrupt the structure of microtubules partially inhibit the increase in water permeability in response to vasopressin and exogenous cyclic AMP in isolated toad urinary bladders.…”

“…For the assay of cyclic AMP-dependent protein kinase, we used the same method as in our earlier experiments (4) with the exception that the initial trichloroacetic acid (TCA) precipitate was dissolved in 0.1 ml of 1 N NaOH and reprecipitated by 5%7 TCA before the final washing on Millipore filters (Millipore Corp., Bedford, Mass.). All assays were run in triplicate.…”

“…Fractions for studies of adenylate cyclase, cyclic AMP phosphodiesterase, and protein kinase activities were prepared in a slightly different way. The plasma membrane fraction was prepared according to the method of Fitzpatrick et al (18) as employed in our previous studies (4). The supernate from the first centrifugation in this procedure was further centrifuged for 60 min at 100,000 g, and the supernate (cytosol) was used as a source of protein kinase and cyclic AMP phosphodiesterase activities.…”