Evidence that forskolin binds to the glucose transporter of human erythrocytes

Journal Article · Sun Oct 25 04:00:00 EST 1987 · J. Biol. Chem.; (United States)

OSTI ID:5784439

Lavis, V R; Lee, D P; Shenolikar, S

Binding of (4-/sup 3/H)cytochalasin B and (12-/sup 3/H)forskolin to human erythrocyte membranes was measured by a centrifugation method. Glucose-displaceable binding of cytochalasin B was saturable, with KD = 0.11 microM, and maximum binding approximately 550 pmol/mg of protein. Forskolin inhibited the glucose-displaceable binding of cytochalasin B in an apparently competitive manner, with K1 = 3 microM. Glucose-displaceable binding of (12-/sup 3/H)forskolin was also saturable, with KD = 2.6 microM and maximum binding approximately equal to 400 pmol/mg of protein. The following compounds inhibited binding of (12-/sup 3/H)forskolin and (4-/sup 3/H)cytochalasin B equivalently, with relative potencies parallel to their reported affinities for the glucose transport system: cytochalasins A and D, dihydrocytochalasin B, L-rhamnose, L-glucose, D-galactose, D-mannose, D-glucose, 2-deoxy-D-glucose, 3-O-methyl-D-glucose, phloretin, and phlorizin. A water-soluble derivative of forskolin, 7-hemisuccinyl-7-desacetylforskolin, displaced equivalent amounts of (4-/sup 3/H)cytochalasin B or (12-/sup 3/H)forskolin. Rabbit erythrocyte membranes, which are deficient in glucose transporter, did not bind either (4-/sup 3/H)cytochalasin B or (12-/sup 3/H)forskolin in a glucose-displaceable manner. These results indicate that forskolin, in concentrations routinely employed for stimulation of adenylate cyclase, binds to the glucose transporter. Endogenous ligands with similar specificities could be important modulators of cellular metabolism.

• Research Organization: Univ. of Texas Medical School, Houston
• OSTI ID: 5784439
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 262:30; ISSN JBCHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL MATERIALS
BLOOD
BLOOD CELLS
BODY FLUIDS
CARBOHYDRATES
CELL CONSTITUENTS
CELL MEMBRANES
CENTRIFUGATION
CPB
ERYTHROCYTES
GLUCOSE
HEXOSES
IN VITRO
INHIBITION
ISOTOPE APPLICATIONS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MAN
MATERIALS
MEMBRANE TRANSPORT
MEMBRANES
MONOSACCHARIDES
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
RABBITS
REACTION KINETICS
RESPONSE MODIFYING FACTORS
SACCHARIDES
SEPARATION PROCESSES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ULTRACENTRIFUGATION
VERTEBRATES