A Drosophila gene encoding a homologue of vertebrate arrestin was isolated by subtractive hybridization and identified as member set genes that are preferentially expressed in the visual system. This encodes 364-amino acid protein displays greater than 40% amino sequence identity with human bovine arrestin. Interestingly, lacks C-terminal sequences were postulated to interact rhodopsin during quenching phototransduction cascade response. These findings discussed terms invertebrate...

A distant relative of catalase that is specialized for metabolism a fatty acid hydroperoxide was identified. This heme peroxidase occurs in coral as part fusion protein, the other component which lipoxygenase forms substrate. The end product an unstable epoxide (an allene oxide) potential precursor prostaglandin-like molecules. These results extend known chemistry catalase-like proteins and reveal distinct type enzymatic construct involved polyunsaturated acids.

Lipoxygenases that form S configuration fatty acid hydroperoxides have been purified or cloned from plant and mammalian sources. Our objectives were to characterize one of the lipoxygenases with R stereospecificity, many which are described in marine freshwater invertebrates. Characterization primary structure an R-specific enzyme should help provide a new perspective consider enzyme-substrate interactions basis specificity all lipoxygenases. We 8R-lipoxygenase prostaglandin-containing coral...

Visual transduction in Drosophila is a G protein-coupled phospholipase C-mediated process that leads to depolarization via activation of the transient receptor potential (TRP) calcium channel. Inactivation-no-afterpotential D (INAD) an adaptor protein containing PDZ domains known interact with TRP. Immunoprecipitation studies indicate INAD also binds eye-specific kinase C and C, no-receptor-potential A (NORPA). By overlay assay site-directed mutagenesis we have defined essential elements...

Cyclophilins, the intracellular receptors for widely used immunosuppressant cyclosporin A have been found to be peptidyl-prolyl cis/trans isomerases and implicated in protein folding trafficking. The Drosophila ninaA gene encodes a photoreceptor-specific cyclophilin homolog involved rhodopsin biogenesis. mutants 90% reduction levels of Rh1 rhodopsin. To gain insight into role cyclophilins vivo, we carried out genetic screen designed identify functionally important regions protein. Over...

Drosophila eye-specific protein kinase C (eye-PKC) is involved in light adaptation and deactivation. eye-PKC, NORPA (phospholipase Cβ), transient-receptor-potential (TRP) (calcium channel) are integral components of a signal transduction complex organized by INAD, containing five PDZ domains. We previously demonstrated the direct association between third domain INAD with TRP addition to carboxyl-terminal half last three residues NORPA. In this work, molecular interaction eye-PKC defined via...

Human alpha 2-antiplasmin readily forms 1:1 complexes with either trypsin or chymotrypsin at independent but overlapping reactive sites. In the absence of 2-macroglobulin, complex dissociation and enzyme release can be demonstrated without regeneration inhibitory activity. However, in presence this inhibitor 2-antiplasmin-chymotrypsin 2-antiplasmin-trypsin complexs yields functionally active inhibitors which now inactivate chymotrypsin, respectively. These results clearly indicate that...

Although it has been hypothesized that the synteny between mouse and human genes provides an approach to localization of determine quantitative traits in humans, this yet be demonstrated. We tested with two traits, plasma apolipoprotein A-II (apoAII) free fatty acid (FFA) levels. ApoAII is second most abundant protein high density lipoprotein particles, but its function remains largely unknown. now show that, a backcross strains Mus spretus C57BL/6J, apoAII levels correlate FFA...

Abstract Human alpha 2-antiplasmin rapidly forms a stable, equimolar complex with either its target enzyme, plasmin, or trypsin. Perturbation of the inhibitor-trypsin results in peptide bond cleavage at reactive site inhibitor concomitant release small fragment which apparently represents carboxyl-terminal segment inhibitor. Sequence analysis this fragment, together that an overlapping obtained by treatment native Staphylococcus aureus V8 proteinase human neutrophil elastase, yields data...

Drosophila visual signaling is one of the fastest G-protein-coupled transduction cascades, because effector and modulatory proteins are organized into a macromolecular complex ("transducisome"). Assembly orchestrated by inactivation no afterpotential D (INAD), which colocalizes transient receptor potential (TRP) Ca2+ channel, phospholipase Cbeta, eye protein kinase C (eye-PKC), for more efficient signal transduction. Eye-PKC critical deactivation vision. Moreover, regulated interaction...

We have investigated the mechanisms responsible for increase in acetylcholine receptor subunit mRNAs during induction of denervation supersensitivity skeletal muscle. Using a cRNA probe specific exon 7 (224 nucleotides; with flanking intron sequences 105 nucleotides on 3' end, and 70 5' end) alpha chicken muscle gene, we were able to quantitate concentration mature mRNA its precursor. In 3-wk-old chicks, message leg was found be 4.0 attomoles per microgram total RNA, 40-fold within 1 wk...

In the Drosophila visual cascade, transient receptor potential (TRP) calcium channel, phospholipase Cβ (no-receptor-potential A), and an eye-specific isoform of protein kinase C (eye-PKC) comprise a multimolecular signaling complex via their interaction with scaffold INAD. Previously, we showed that between INAD eye-PKC is prerequisite for deactivation light response, suggesting phosphorylates proteins in complex. To identify substrates eye-PKC, immunoprecipitated from head lysates using...

Arrestins belong to a family of multifunctional adaptor proteins that regulate internalization diverse receptors including G-protein-coupled (GPCRs). Defects associated with endocytosis GPCRs have been linked human diseases. We used enhanced green fluorescent protein-tagged arrestin 2 (Arr2) monitor the turnover major rhodopsin (Rh1) in live Drosophila. demonstrate during degeneration norpA(P24) photoreceptors loss Rh1 is parallel disappearance rhabdomeres, specialized visual organelle...

Arrestin regulates many facets of G-protein coupled receptor signaling. In Drosophila, 1 (Arr1) is expressed at a lower level than 2 (Arr2), and the role Arr1 in visual physiology less understood. Here we generated transgenic flies expressing enhanced green fluorescent protein tagged (Arr1-eGFP) explored its trafficking live photoreceptors. We show that Arr1-eGFP localized cytoplasm displays light-dependent translocation to rhabdomere possibly by interacting with photoactivated rhodopsin...

Ca(2+) modulates the visual response in both vertebrates and invertebrates. In Drosophila photoreceptors, an increase of cytoplasmic mimics light adaptation. Little is known regarding mechanism, however. We explored role sole Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) to mediate CaMKII has been implicated phosphorylation arrestin 2 (Arr2). However, functional significance Arr2 remains debatable. identified retinal by anti-CaMKII antibodies its Ca(2+)-dependent...

J. Neurochem . (2008) 104, 1526–1535. Abstract Drosophila transient‐receptor‐potential (TRP) is a Ca 2+ channel responsible for the light‐dependent depolarization of photoreceptors. TRP anchored to macromolecular complex by tethering inactivation‐no‐afterpotential D (INAD). We previously reported that INAD associated with carboxyl tail via its third post‐synaptic density protein 95, discs‐large, zonular occludens‐1 domain. In this paper, we further explored molecular basis interaction and...

Drosophila visual signaling, a G-protein-coupled phospholipase Cβ (PLCβ)-mediated mechanism, is regulated by eye-protein kinase C (PKC) that promotes light adaptation and fast deactivation, most likely via phosphorylation of inactivation no afterpotential D (INAD) TRP (transient receptor potential). To reveal the critical phosphatases dephosphorylate INAD, we used several biochemical analyses identified protein phosphatase 2A (PP2A) as candidate. Importantly, catalytic subunit PP2A,...