Monoclonal antibodies that bind the renal Na/sup +//glucose symport system. 2. Stabilization of an active conformation

Journal Article · Tue Sep 08 04:00:00 EDT 1987 · Biochemistry; (United States)

OSTI ID:5723175

Wu, J S.R.; Lever, J E

Conformation-dependent fluorescein isothiocyanate (FITC) labeling of the pig renal Na/sup +//glucose symporter was investigated with specific monoclonal antibodies (MAb's). When renal brush border membranes were pretreated with phenyl isothiocyanate (PITC), washed, and then treated at neutral pH with FITC in the presence of transporter substrates Na/sup +/ and glucose, most of the incorporated fluorescence was associated with a single peak after resolution by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The apparent molecular mass of the FITC-labeled species ranged from 79 to 92 kDa. Labeling of this peak was specifically reduced by 70% if Na/sup +/ and glucose were omitted. Na/sup +/ could not be replaced by K/sup +/, Rb/sup +/, or Li/sup +/. FITC labeling of this peak was also stimulated after incubation of membranes with MAb's known to influence high-affinity phlorizin binding, and stimulation was synergistically increased when MAb's were added in the presence of Na/sup +/ and glucose. Substrate-induced or MAb-induced labeling correlated with inactivation of Na/sup +/-dependent phlorizin binding. MAb's recognized an antigen of 75 kDa in the native membranes whereas substrate-induced FITC labeling was accompanied by loss of antigen recognition and protection from proteolysis. These findings are consistent with a model in which MAb's stabilize a Na/sup +/-induced active conformer of the Na/sup +//glucose symport system.

• Research Organization: Univ. of Texas Medical School, Houston
• OSTI ID: 5723175
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 26:18; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
ALKALI METAL COMPOUNDS
ANIMALS
ANTIBODIES
ANTIGENS
AROMATICS
BODY
CARBOHYDRATES
CARBOXYLIC ACIDS
CATIONS
CHARGED PARTICLES
DOMESTIC ANIMALS
DOSE-RESPONSE RELATIONSHIPS
DYES
FLUORESCEIN
GLUCOSE
GLYCOSIDES
HEXOSES
HYDROXY ACIDS
HYDROXY COMPOUNDS
IONS
KETONES
KIDNEYS
LABELLED COMPOUNDS
MAMMALS
MEMBRANE TRANSPORT
MOLECULAR STRUCTURE
MONOCLONAL ANTIBODIES
MONOSACCHARIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
PHENOLS
PHLORIZIN
POLYPHENOLS
SACCHARIDES
SODIUM COMPOUNDS
SWINE
TRITIUM COMPOUNDS
VERTEBRATES