C Montell

..Each of the TRP subfamilies are represented by members in worms and flies, providing the potential for using genetic approaches to characterize the normal functions and activation mechanisms of these channels...

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..In this review, I focus on recent advances in the fly visual system, including the discovery of a visual cycle and insights into the machinery and mechanisms involved in generating a light response in photoreceptor cells...

..The characterization of this complex has led to a re-evaluation of the mechanisms underlying the activation and deactivation of the phototransduction cascade...

..Insights gleaned from mechanistic studies offered the potential for new therapeutic approaches to combat a variety of diseases resulting from alterations in Ca2+ homeostasis...

..Recent studies suggest that alterations in the activities of SOC and TRP channels may be at the heart of several additional neurodegenerative diseases. Thus, TRP channels may prove to be important new targets for drug discovery...

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..Moreover, the biological roles of TRP channels appear to be equally diverse and range from roles in pain perception to male aggression...

..As a result, the repertoire of biological roles attributed to Drosophila TRPs has increased considerably and is likely to lead to many additional surprises over the next few years...

..Several GRs appear to be expressed in multiple cell types that are not associated with contact chemosensation raising the possibility that these proteins may have roles that extend beyond the detection of tastants and pheromones...

..Recent studies have provided strong evidence that at least one TRP channel, TRPV1, is also essential for the maintenance of internal body temperature...

..A recent study has shown that TRP channels are required for hygrosensation in Drosophila, further expanding the repertoire of sensory modalities mediated by TRP channels...

..2007) now show that a PDZ domain in INAD, a scaffold protein in photoreceptor cells of the fruit fly, undergoes a light-dependent conformational change, which has important consequences for signaling and animal behavior...

..Mutations in many TRP channels result in disease, including a variety of sensory impairments...

..Cheng et al. (2010) now demonstrate that the calcium-permeable channel TRPV3 is required for these EGFR-dependent functions...

..These results strongly support the model that a DAG metabolite is critical for TRP activation and suggest that mammalian DAG lipases may play similar roles...

..Recent work on the mouse ANKTM1 and Drosophila Painless proteins shows that members of a third TRP subfamily, TRPN, also function in thermosensation...

..As many of these functions may be conserved among the mammalian TRPs, the invertebrate TRPs offer valuable genetic handles for characterizing the functions of these cation channels in vivo...

..Recent studies demonstrate that these 'chanzymes' are essential for Mg(2+) homeostasis, which is critical for human health and cell viability...

..Thus, it appears that calmodulin functions as a Ca2+ sensor for a broad diversity of retinal proteins, some of which are implicated in synaptic transmission...

..Thus, we propose that the INAD supramolecular complex is a higher order signaling web consisting of an extended network of INAD molecules through which a G protein-coupled cascade is tethered...

..While TRPL and TRPgamma homomultimers are constitutively active, we demonstrate that TRPL-TRPgamma heteromultimers form a regulated phospholipase C- (PLC-) stimulated channel...

..Rather, the primary function of the TRP/ INAD complex is to form the core unit required for localization of the signalplex to the rhabdomeres...

..The human TRP-related proteins may mediate many of the store-operated conductances that have been identified previously in a plethora of human cells...

..Disruption of the NINAC/INAD interaction delayed termination of the photoreceptor response. Thus one role of this signaling complex is in rapid deactivation of the photoresponse...

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..We propose that the light-activated current in photoreceptor cells is produced by a combination of TRP homo- and TRP-TRPL heteromultimers...

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..The repo gene encoded a homeo domain protein suggesting that it might be a transcriptional regulator of genes required for glial development...

..This phenotype suggests that a mechanism exists to prevent reactivation of the visual cascade and that p174 participates in this process...

..The INAD complex does not appear to be a particle, but a massive signaling web composed of an INAD polymer with which some of the target proteins associate through complex multivalent interactions...

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..A general function of unconventional myosins may be to control the subcellular distribution of calmodulin...

..Furthermore, disruption of this interaction results in retinal degeneration. We propose that the TRP channel is linked to NORPA and RH1 to facilitate feedback regulation of these upstream signaling molecules...

..These results suggest that calmodulin binding to both C1 and C2 is required in vivo for termination of phototransduction...

..This retinal degeneration was greatly suppressed by elimination of the Na(+)/Ca(2+) exchanger, CalX, indicating that the cell death was due primarily to deficient Ca(2+) entry rather than disruption of the TRP-anchoring function...

..TRPC1 was expressed at the highest levels in the fetal brain and in the adult heart, brain, testis, and ovaries. Evidence is also presented that TRPC1 represents the archetype of a family of related human proteins...

..While Ric and RIT were widely expressed, expression of RIN was confined to the neuron system...

..These results illustrate the critical role of Ca(2+) for proper signaling and provide genetic evidence that Ca(2+) overload is responsible for a form of retinal degeneration resulting from defects in the TRP channel...

..Moreover, this work demonstrates that a PLCbeta derivative that does not promote TRP channel activation, still contributes to signaling in vivo...

..We propose that control of translocation through interaction between MLSN-S and MLSN-L represents a mode for regulating ion channel activity...

..We propose that the msi protein regulates sensillum development by controlling the expression of target genes at the posttranscriptional level...

..We propose that p69 is required to repress expression of genes that are incompatible with development of photoreceptor cell fates, whereas p88 appears to be required to repress genes that promote the R7 cell fate...

..In addition, DPR defines a large previously unknown group of > or =20 highly related Ig-containing proteins...

..Moreover, our data implicate Drosophila retinal pigment cells as functioning in the conversion of dietary all-trans-retinol to 11-cis-retinal and suggest that these cells are the closest invertebrate equivalent to the RPE...

..These data point to an evolutionarily conserved role for GPRK1 in modulating the amplitude of the visual response...

..It has been presumed that the visual impairment resulting from long-term, continuous exposure to ambient light is a secondary consequence of the effects of light on retinal morphology, but this has not been addressed...

..This suggests that the p174 myosin-I type tail is the domain responsible for association with the rhabdomeres and that the substrate for the p174 putative kinase may be a rhabdomeric protein important in photo-transduction...

..Another class B scavenger receptor, NINAD, functions upstream of SANTA MARIA in the uptake of carotenoids, enabling us to propose a pathway involving multiple extraretinal cell types and proteins essential for the formation of rhodopsin...

..These data demonstrate that the light-dependent translocation of Arr2 into the rhabdomeres requires PI-mediated interactions between Arr2 and the NINAC myosin III...

..We conclude that the decision to select the preferred over slightly cooler temperatures requires iav and is achieved by activating chordotonal neurons, which in turn induces repulsive behaviors, due to an increase in high angle turns...

..The genetic interactions with both rdgA and Pld indicate that Laza functions in the convergence of both PLC- and PLD-coupled signaling in vivo...

..Given that mammalian TRPA1 is required for responding to noxious chemicals, many of which cause pain and injury, our analysis underscores the evolutionarily conserved role for TRPA1 channels in chemical avoidance...

..TRP channels are important for human health as mutations in at least four TRP channels underlie disease...

..Our findings demonstrate that light-induced translocation of Arr2 occurs through a noncanonical rhodopsin/Rac2 pathway, which is distinct from the classical phototransduction cascade...

..Since phospholipase C activity is required for activation of Drosophila phototransduction, these data point to a dual role of PIs in phototransduction...

..Genetic deletion of p53 suppresses neurodegeneration in mHtt-Tg flies and neurobehavioral abnormalities of mHtt-Tg mice. Our findings suggest that p53 links nuclear and mitochondrial pathologies characteristic of HD...

..Thus, rather than regulating GR trafficking, GR33a may be a coreceptor required for sensing all nonvolatile repulsive chemicals, including tastants and pheromones...

..Subsequent to the laminar cell death, the retinal cells in the repo visual system also degenerated, indicating that the retinal cell death was due to retrograde degeneration...

..The finding that Amo functions in sperm flagella supports a common and evolutionarily conserved role for polycystin-2 proteins in both motile and nonmotile axonemal-containing structures...

..Since 0.02% DEET elicited action potentials, we conclude that DEET directly activates of GRNs. We suggest that the effectiveness of DEET in pest control owes to its dual action in inducing avoidance simultaneously via GRNs and ORNs...

..We conclude that the slower termination of the photoresponse in retin(1) resulted from a requirement for the Retin/NINAC complex for stability of INAD and PKC...

..We propose that lysosomal tetraspanins in mammalian cells may also function in the downregulation of rhodopsin and other G-protein-coupled receptors, in response to intense or prolonged agonist stimulation...

..Thus, the fruitfly continues to provide a valuable in vivo model to characterize the functions, interacting partners and activation mechanisms of TRP-related proteins...

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..These data suggest that Drosophila sugar receptors function as multimers and that Gr64f is required broadly as a coreceptor for the detection of sugars...

..We propose that activation of TRPA1 through a signaling cascade promotes amplification of small differences in temperature and facilitates adaptation to temperatures within the comfortable range...

..These data demonstrate that multiple Grs are coexpressed with Gr5a and that Drosophila Gr64a is required for the responses to multiple sugars...

..2. We propose that regulation of CaM binding by PIs provides a mode for integration of channel regulation by Ca(2+) and PIs...

..Because the dpis1 mutation eliminates production of an enzyme essential for PIP2 regeneration, our data argue against activation of TRP and TRPL through a reduction of inhibitory PIP2...

..Gr66a is the first gustatory receptor shown to be essential for caffeine-induced behavior and activity of gustatory receptor cells in vivo...

..The voltage modulation and rapid kinetics provide TRPM5 with an excellent set of properties for participating in signaling in taste receptors and other excitable cells...

..Since hematopoietic cells in humans are involved in clearance of apoptotic cells, our results raise the possibility that bone marrow transplantation may limit the progression of MLIV...

..These flies may provide a useful model for studying LRRK2-linked pathogenesis and for future therapeutic screens for PD intervention...

..However, a visual cycle is thought to be absent in invertebrates such as the fruit fly Drosophila melanogaster...

..We found that Asp621 mutations profoundly affected several key aspects of the light response and caused light-dependent retinal degeneration...

..We conclude that the activation of the Ras cascade may be an important in vivo requisite to the transduction of signals through RIC and that the binding of calmodulin to RIC may negatively regulate this small GTPase...

..The complete Compendium, including data tables for each member of the TRP channel family, can be found at http://www.iuphar-db.org/iuphar-ic/...

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..Given the apparent parallels between mammalian and Drosophila taste transduction, these studies should provide important new insights into the mechanisms of gustatory transduction that apply to human taste receptor cells. ..

..Therefore, the proposed studies should contribute to a general understanding of the mechanisms regulating phototransduction, as well as provide new insights into the mechanisms underlying certain forms of retinal degeneration. ..

..Moreover, defects in TRP channels have been associated with changes in growth control and one TRP-related protein, TRPM1, may be a tumor suppressor. ..

..Moreover, defects in TRP channels have been associated with changes in growth control and one TRP-related protein, TRPM1, may be a tumor suppressor. ..

..The topics to be covered at the meeting are of fundamental importance and are relevant to understanding the bases of a diseases such as neurodegeneration, communicative disorders, aging, cancer, kidney and cardiovascular disease. ..

..The long-term goal of the proposed research is to identify new therapies to reduce the severities of human retinal degenerations. ..

..Given the apparent parallels between mammalian and Drosophila taste transduction, these studies should provide important new insights into the mechanisms of gustatory transduction that apply to human taste receptor cells. ..

..The long-term goal of the proposed research is to identify new therapies to reduce the severities of human retinal degenerations. ..

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..Given that the molecular mechanisms underlying the activation of these human TRPs are poorly understood, Drosophila TRP provides an in vivo model for defining the mechanisms regulating TRP channels. ..

..Given the apparent parallels between mammalian and Drosophila taste transduction, these studies should provide important new insights into the mechanisms of gustatory transduction that apply to human taste receptor cells. ..

..Moreover, defects in TRP channels have been associated with changes in growth control and one TRP-related protein, TRPM1, may be a tumor suppressor. ..

..A long range goal of the current research will be to ascertain whether similar retinal dystrophies result from mutations in these vertebrate homologs. ..

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..Homologs of many of these molecules may be found in other organisms including humans and may lead to a better understanding of human and may lead to a better understanding of human retinal diseases caused by defects in these molecules...