Activation of K+ channels in renal medullary vesicles by cAMP-dependent protein kinase

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Journal of Membrane Biology; (USA)

DOI:https://doi.org/10.1007/BF01870791· OSTI ID:5364579

Reeves, W B; McDonald, G A; Mehta, P; Andreoli, T E ^[1]

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1. Univ. of Arkansas College of Medicine, Little Rock (USA)

ADH, acting through cAMP, increases the potassium conductance of apical membranes of mouse medullary thick ascending limbs of Henle. The present studies tested whether exposure of renal medullary apical membranes in vitro to the catalytic subunit of cAMP-dependent protein kinase resulted in an increase in potassium conductance. Apical membrane vesicles prepared from rabbit outer renal medulla demonstrated bumetanide- and chloride-sensitive {sup 22}Na+ uptake and barium-sensitive, voltage-dependent {sup 86}Rb+ influx. When vesicles were loaded with purified catalytic subunit of cAMP-dependent protein kinase (150 mU/ml), 1 mM ATP, and 50 mM KCl, the barium-sensitive {sup 86}Rb+ influx increased from 361 {plus minus} 138 to 528 {plus minus} 120 pM/mg prot.30 sec (P less than 0.01). This increase was inhibited completely when heat-stable protein kinase inhibitor (1 microgram/ml) was also present in the vesicle solutions. The stimulation of {sup 86}Rb+ uptake by protein kinase required ATP rather than ADP. It also required opening of the vesicles by hypotonic shock, presumably to allow the kinase free access to the cytoplasmic face of the membranes. We conclude that cAMP-dependent protein kinase-mediated phosphorylation of apical membranes from the renal medulla increases the potassium conductance of these membranes. This mechanism may account for the ADH-mediated increase in potassium conductance in the mouse mTALH.

• OSTI ID: 5364579
• Journal Information: Journal of Membrane Biology; (USA), Vol. 109:1; ISSN 0022-2631
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
PHOSPHOTRANSFERASES
BIOCHEMICAL REACTION KINETICS
POTASSIUM COMPOUNDS
MEMBRANE TRANSPORT
ATP
BARIUM
CELL MEMBRANES
IN VITRO
KIDNEYS
MICE
PHOSPHORYLATION
RUBIDIUM 86
TRACER TECHNIQUES
ALKALI METAL COMPOUNDS
ALKALI METAL ISOTOPES
ALKALINE EARTH METALS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHEMICAL REACTIONS
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYMES
INTERMEDIATE MASS NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
MEMBRANES
METALS
MINUTES LIVING RADIOISOTOPES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANS
PHOSPHORUS-GROUP TRANSFERASES
RADIOISOTOPES
REACTION KINETICS
RODENTS
RUBIDIUM ISOTOPES
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques