In this study, we demonstrate a method to quantify biomarker expression that uses an exogenous dual-reporter imaging approach to improve tumor signal detection. The uptake of two fluorophores, one nonspecific and one targeted to the epidermal growth factor receptor (EGFR), were imaged at 1 h in three types of xenograft tumors spanning a range of EGFR expression levels (n=6 in each group). Using...

Neutrophil functions are initiated within seconds after stimulus addition in response to N-formyl chemotactic peptides and precede ligand-receptor internalization [ 1-51. We have biochemical evidence from subcellular fractionation studies [3, 61 and covalently labelling the receptor by means of a radioiodinated photoactivatable arylazido derivative of the hexapeptide CHO-Nle-Leu-Phe-Nle-Tyr-Lys...

Iron(III)-doped silica nanoshells are shown to possess an in vitro cell-receptor mediated targeting functionality for endocytosis. Compared to plain silica nanoparticles, iron enriched ones are shown to be target-specific, a property that makes them potentially better vehicles for applications, such as drug delivery and tumor imaging, by making them more selective and thereby reducing the nanop...

This protocol describes the labeling of epidermal growth factor receptor (EGFR) on COS7 fibroblast cells, and subsequent correlative fluorescence microscopy and environmental scanning electron microscopy (ESEM) of whole cells in hydrated state. Fluorescent quantum dots (QDs) were coupled to EGFR via a two-step labeling protocol, providing an efficient and specific protein labeling, while avoidi...

Heptahelical receptors (HHRs) are generally thought to function as monomeric entities. Several HHRs such as somatostatin receptors (SSTRs), however, form homo- and heterooligomers when activated by ligand binding. By using dual fluorescent ligands simultaneously applied to live cells monotransfected with SSTR5 (R5) or SSTR1 (R1), or cotransfected with R5 and R1, we have analyzed the ligand rece...

Hormones integrate the activities of their target cells through receptor-modulated cascades of protein interactions that ultimately lead to changes in cellular function. Understanding how the cell assembles these signaling protein complexes is critically important to unraveling disease processes, and to the design of therapeutic strategies. Recent advances in live-cell imaging technologies, com...

Steroid hormone receptors comprise a major class of therapeutic drug targets that control gene expression by binding steroid hormone ligands. These small molecule-protein interactions are typically characterized in living cells by quantification of ligand-mediated reporter gene expression. As an alternative, non-transcriptional approach, we constructed fluorescent cellular sensors by expressing...

The best characterized role for ubiquitination of membrane receptors is to negatively regulate signaling by targeting receptors for lysosomal degradation. The high affinity receptor for IgE (FcepsilonRI) expressed on mast cells and basophils is rapidly ubiquitinated upon antigen stimulation. However, the nature and the role of this covalent modification are still largelly unknown. Here, we show...

OBJECTIVES To characterize glucocorticoid receptor expression in peripheral WBCs of critically ill children using flow cytometry. DESIGN Prospective observational cohort. SETTING A university-affiliated, tertiary PICU. PATIENTS Fifty-two critically ill children. INTERVENTIONS Samples collected for measurement of glucocorticoid receptor expression and parallel cortisol levels. MEASUREM...

background: among diverse protein purification systems, affinity chromatography is the most attractive one in the purification process of coagulation factors. coagulation factor vii is a plasma serine protease that has a significant role in natural human hemostasis and its recombinant form such as aryoseventm, has been applied in clinical treatment of bleeding disorders. immunoaffinity chromato...