Characterization of dihydropyridine-sensitive calcium channels

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:7152128

Horne, W A

The structural and regulatory properties of the dihydropyridine-sensitive calcium channel were studied by isolating protein components of the channel complex from both cardiac and skeletal muscle. Hydrodynamic characterization of the (+)-({sup 3}H)PN200-110-labeled cardiac calcium channel revealed that the protein components of the complex had a total molecular mass of 370,000 daltons, a Stokes radius of 86 {angstrom}, and a frictional ratio of 1.3. A technique is described for the rapid incorporation of the CHAPS solubilized skeletal muscle calcium channel complex into phospholipid vesicles. {sup 45}Ca{sup 2+} uptake into phospholipid vesicles containing calcium channels was inhibited by phenylalkalamine calcium antagonists. Wheat germ lectin followed by DEAE chromatography of the CHAPS solubilized complex resulted in the dissociation of regulatory components of the complex from channel components. The DEAE preparation gave rise to {sup 45}Ca{sup 2+} uptake that was not inhibited by verapamil but was inhibited by GTPgS activated G{sub 0}. The inhibition of {sup 45}Ca{sup 2+} uptake by verapamil was restored by co-reconstitution of wash fractions from wheat germ lectin chromatography. Phosphorylation of polypeptides in this fraction by polypeptide-dependent protein kinase prevented the restoration of verapamil sensitivity. The partial purification of an endogenous skeletal muscle ADP-ribosyltransferase is also described. ADP-ribosylation of the {alpha}{sub 2} subunit of the calcium channel complex is enhanced by polylysine and inhibited by GTP{gamma}S, suggesting that regulation of this enzyme is under the control of GTP binding proteins. These results suggest a complex model, involving a number of different protein components, for calcium channel regulation in skeletal muscle.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 7152128
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL FUNCTIONS
BODY
CALCIUM 45
CALCIUM COMPOUNDS
CALCIUM ISOTOPES
CARDIOVASCULAR SYSTEM
DATA
DAYS LIVING RADIOISOTOPES
ESTERS
EVEN-ODD NUCLEI
EXPERIMENTAL DATA
FUNCTIONS
HEART
HYDROGEN COMPOUNDS
INFORMATION
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
LIPIDS
MEMBRANE TRANSPORT
MUSCLES
NUCLEI
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANS
PHOSPHOLIPIDS
RADIOISOTOPES
SKELETON
TRACER TECHNIQUES
TRITIUM COMPOUNDS
UPTAKE