TY - JOUR
T1 - The Drosophila light-activated TRP and TRPL channels - Targets of the phosphoinositide signaling cascade
AU - Katz, Ben
AU - Minke, Baruch
N1 - Publisher Copyright:
© 2018 Elsevier Ltd
PY - 2018/9
Y1 - 2018/9
N2 - The Drosophila light-activated Transient Receptor Potential (TRP) channel is the founding member of a large and diverse family of channel proteins. It is now established that TRP channels are evolutionarily conserved and are found in many organisms and tissues. This review outlines the progress made in our understanding of Drosophila phototransduction with a focus on the light sensitive TRP channels. The visual system of Drosophila has remarkable capabilities, such as single photon sensitivity, low dark noise, wide dynamic range of responses to changing ambient light intensities and an unusually wide range of frequency responses to modulated lights. These capabilities are obtained by a unique cellular structure called rhabdomere, which contains ∼40,000 microvilli, harboring a sophisticated molecular machinery performing phototransduction. The phototransduction cascade was discovered mainly by using the power of Drosophila molecular genetics and the ability to generate mutations in virtually every gene of the cascade. This allowed a detailed functional analysis and mechanistic description of the phototransduction cascade. Drosophila phototransduction has been a model system, instrumental for studying phosphoinositide signaling and its participation in TRP channel activation. Accordingly, the phosphoinositide signaling cascade activates the TRP/TRPL channels via Gq-protein-mediated PLCβ while the gating mechanism of the channels following PLC activation is still under debate. Detailed studies of the single photon response (quantum bump) and the spontaneous dark bump has given important tools to investigate critical features of channel activation and regulation including: synchronization in channel activity, the existence of a Ca 2+ regulated threshold of channel activation, positive and negative feedback and refractory period in bump generation. We anticipate that studies in Drosophila photoreceptors will continue shed light on mechanisms that operate in mammalian TRP channels.
AB - The Drosophila light-activated Transient Receptor Potential (TRP) channel is the founding member of a large and diverse family of channel proteins. It is now established that TRP channels are evolutionarily conserved and are found in many organisms and tissues. This review outlines the progress made in our understanding of Drosophila phototransduction with a focus on the light sensitive TRP channels. The visual system of Drosophila has remarkable capabilities, such as single photon sensitivity, low dark noise, wide dynamic range of responses to changing ambient light intensities and an unusually wide range of frequency responses to modulated lights. These capabilities are obtained by a unique cellular structure called rhabdomere, which contains ∼40,000 microvilli, harboring a sophisticated molecular machinery performing phototransduction. The phototransduction cascade was discovered mainly by using the power of Drosophila molecular genetics and the ability to generate mutations in virtually every gene of the cascade. This allowed a detailed functional analysis and mechanistic description of the phototransduction cascade. Drosophila phototransduction has been a model system, instrumental for studying phosphoinositide signaling and its participation in TRP channel activation. Accordingly, the phosphoinositide signaling cascade activates the TRP/TRPL channels via Gq-protein-mediated PLCβ while the gating mechanism of the channels following PLC activation is still under debate. Detailed studies of the single photon response (quantum bump) and the spontaneous dark bump has given important tools to investigate critical features of channel activation and regulation including: synchronization in channel activity, the existence of a Ca 2+ regulated threshold of channel activation, positive and negative feedback and refractory period in bump generation. We anticipate that studies in Drosophila photoreceptors will continue shed light on mechanisms that operate in mammalian TRP channels.
KW - Drosophila TRP and TRPL
KW - Gq-protein
KW - Phosphoinositide signaling
KW - Phospholipase C
KW - Phototransduction
KW - Single photon response
UR - http://www.scopus.com/inward/record.url?scp=85047244697&partnerID=8YFLogxK
U2 - 10.1016/j.preteyeres.2018.05.001
DO - 10.1016/j.preteyeres.2018.05.001
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C2 - 29738822
AN - SCOPUS:85047244697
SN - 1350-9462
VL - 66
SP - 200
EP - 219
JO - Progress in Retinal and Eye Research
JF - Progress in Retinal and Eye Research
ER -