The Ca2+-sensitive photoprotein aequorin (Mr = 20,000) was introduced into human blood platelets by incubation with 10 mM EGTA and 5 mM ATP. Platelet cytoplasmic and granule contents were retained during the loading procedure, and platelet morphology, aggregation, and secretion in response to agonists were normal after aequorin loading. Luminescence indicated an apparent resting cytoplasmic ion...

Modification studies of the 5 histidine residues in aequorin employing site-directed mutagenesis and diethyl pyrocarbonate suggested that His169 may be the site of binding of molecular oxygen in aequorin. The modification of this residue led to complete loss of activity, whereas modification of the remaining 4 histidine residues yielded mutant aequorins with varying bioluminescence activities.

Exogenous expression of pharmacological targets in transformed cell lines has been the traditional platform for high throughput screening of small molecules. However, exogenous expression in these cells is limited by aberrant dosage, or its toxicity, the potential lack of interaction partners, and alterations to physiology due to transformation itself. Instead, primary cells or cells differenti...

1. The uptake of liposomes containing the photoprotein obelin by rat isolated adipocytes was investigated with the aim of producing liposome-cell fusion, enabling obelin to be introduced into the cytoplasm of intact cells. 2. Incubation of liposomes containing obelin with rat isolated adipocytes resulted in a time-dependent uptake of entrapped obelin by the adipocytes. The uptake by adipocytes ...