Prolonged exposure of cells or tissues to drugs or hormones such as catecholamines leads to a state of refractoriness to further stimulation by that agent, known as homologous desensitization. In the case of the beta-adrenergic receptor coupled to adenylate cyclase, this process has been shown to be intimately associated with the sequestration of the receptors from the cell surface through a cA...

The Madin-Darby canine kidney (MDCK) cell line, derived from distal tubule/collecting duct, expresses differentiated properties of renal tubule epithelium in culture. We studied the expression of adrenergic receptors in MDCK to examine the role of catecholamines in the regulation of renal function. Radioligand-binding studies demonstrated, on the basis of receptor affinities of subtype-selectiv...

Zymosan is a beta-glucan- and mannan-rich particle that is widely used as a cellular activator for examining the numerous responses effected by phagocytes. The macrophage mannose receptor (MR) and complement receptor 3 (CR3) have historically been considered the major macrophage lectins involved in the nonopsonic recognition of these yeast-derived particles. Using specific carbohydrate inhibito...

PURPOSE Bladder symptoms can be ameliorated by sex steroids but to our knowledge the mechanism of action is unknown. Previous studies of steroid receptor expression in the bladder did not indicate receptor subtype expression. We report the distribution of estrogen and progesterone receptor isoforms in the female lower urinary tract. MATERIALS AND METHODS Prospectively recruited women undergoi...

The presence of active transforming growth factor-beta (TGF-beta) in serum has not been widely accepted. In particular, although at least five studies have concluded that active TGF-beta is present in normal human plasma and serum, assays that use the extracellular domain of the TGF-beta type II receptor as a capture agent have given contradictory results. We show that there is an antagonist pr...

Loss of sensitivity to growth inhibition by transforming growth factor (TGF)-beta is a phenomenon often observed in human epithelial tumor cells and is linked to malignant progression. We tested a panel of estrogen receptor (ER)-positive and -negative breast cell lines for their sensitivity to TGF-beta and a related member of the TGF-beta superfamily, activin. Both TGF-beta-sensitive (MCF7, Hs5...

The transforming growth factor beta (TGF-beta) family of growth factors control proliferation, extracellular matrix synthesis and/ or differentiation in a wide variety of cells. However, the molecular mechanisms governing ligand binding, receptor oligomerization and signal transduction remain incompletely understood. In this study, we utilized a set of antibodies selective for the extracellular...

We recently demonstrated that nonvisual arrestins interact via a C-terminal binding domain with clathrin and function as adaptor proteins to promote beta2-adrenergic receptor (beta2AR) internalization. Here, we investigated the potential utility of a mini-gene expressing the clathrin-binding domain of beta-arrestin (beta-arrestin (319-418)) to function as a dominant-negative with respect to bet...

Lipomas are benign tumors that consist of mature adipocytes. Most lipomas sporadic, but some familial conditions predispose affected individuals to the development up thousands lipomas. Currently, no targeted treatments exist. To develop such an agent, cellular composition must be elucidated. Using single-cell resolution techniques, we have successfully begun characterize transcriptomic landsca...