Photoaffinity labelling of juvenile hormone binding proteins in the cockroach Leucophaea maderae

Larva lights: a decade of photoaffinity labeling with juvenile hormone analogues

The introduction of photoaffinity labeling into the mode of action of insect hormones and pheromones started 12 yr ago with the photoaffinity labeling of juvenile hormone binding proteins (JHBPs) from cockroaches in the laboratory of the late John K. Koeppe. Applying this technique to Manduca sexta led ultimately to a three-laboratory collaborative project that has begun to dissect the molecular basis for JH transport, metabolism, and nuclear binding and gene activation in Lepidoptera. This review provides (1) a history of the first experiments; (2) an idea of the breadth of the technique in the arthropod classes Insecta, Crustacea, and Arachnida; and (3) evidence for the depth of the technique in unearthing key details about three different types of the molecular action of JH in M. sexta.

Characterization of the proteins from Melanoplus bivittatus that bind juvenile hormone, and a refined EFDA photolabeling technique

1. Juvenile hormone (JH) is specifically bound by a protein from hemolymph and fat body cytosol of the grasshopper, Melanoplus bivittatus. 2. This protein has a native molecular weight of 331,000 and subunits of 77,000. 3. Proteins that bind JH were covalently photolabeled with a JH analog, epoxyfarnesyl diazoacetate (EFDA). Samples were irradiated in spot plates and hydroxyapatite was used to separate bound from free [3H]EFDA. Differential solubilization was used to extract unlinked [3H]EFDA and solubilize [3H]EFDA linked to protein. 4. Hemolymph proteins of M(r) 479,000, 240,000 and 77,000 also bound [3H]EFDA. 5. Proteins that bound [3H]EFDA were not vitellogenins.

Chemistry of pheromone and hormone metabolism in insects

Chemical evidence is needed in both insect endocrinology and sensory physiology to understand hormone and pheromone action at the molecular level. Radiolabeled pheromones and hormones have been synthesized and used to identify binding and catabolic proteins from insect tissues. Chemically modified analogs, including photoaffinity labels and enzyme inhibitors, are among the tools used to covalently modify the specific acceptor or catalytic sites. Such targeted agents can also provide leads for the design of growth and mating disruptants by allowing manipulation of the physiologically important interactions of the chemical signals with macromolecules.