PMID: 2483679Jan 1, 1989Paper

Fluorescence labeling of proteins related to ADH-induced change in frog bladder luminal membrane.

Biology of the Cell
G ValentiM Svelto

Abstract

Sulfhydryl (SH) reactive reagents, such as eosin derivatives, have been found to be useful in labeling water pathways in red cells. In the present study we used an impermeable SH-reagent, a fluorescent maleimide analogue EMA (eosin-5'-maleimide), in order to identify proteins involved in water permeability response to antidiuretic hormone (ADH). We observed that: 1) EMA (1 mM) mucosal pretreatment did not modify either the basal water flux or the subsequent ADH-induced hydrosmotic response; 2) EMA added to the mucosal bath at the maximum response to ADH, significantly decreased net water flux by about 40%; similar results were obtained when 10(-5) M forskolin was used as a hydrosmotic agent. These results suggest that the inhibitory effect of EMA occurs at a post cAMP step, possibly at the level of the sulfhydryl groups of the water channels themselves. Fluorescence distribution in SDS-PAGE of Triton X-100 extracted proteins from bladder labeled with EMA in both control conditions and under ADH stimulation allowed us to identify apical membrane proteins, labeled during ADH stimulation and not labeled in water impermeable controls. Of particular importance are four proteins of 52, 32-35, 26, 17, kDa. These polypeptides are proba...Continue Reading

Citations

Oct 1, 1993·Pediatric Nephrology : Journal of the International Pediatric Nephrology Association·H W HarrisM L Zeidel
Aug 24, 1999·The European Journal of Neuroscience·V Ramírez-LeónB Ulfhake
May 19, 2006·Biology of the Cell·Cveta TomovaBruno M Humbel
Apr 25, 2007·Traffic·Elly van DonselaarJan W Slot

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