Isolation, Cloning, and Characterisation of a <i>trp</i> Homologue from Squid (<i>Loligo forbesi</i>) Photoreceptor Membranes

Monk, Phillip; Carne, Alan; Liu, Shuhua; Ford, John W.; Keen, Jeffrey N.; Findlay, John B. C.

doi:10.1046/j.1471-4159.1996.67062227.x

Cited by 29 publications

(16 citation statements)

References 29 publications

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“…They were first identified in Drosophila rhabdomeric photoreceptors (Montell and Rubin, 1989;Hardie and Minke, 1992), and TRP channel homologues have also been found in limulus (Bandyopadhyay and Payne, 2004) and squid (Monk et al, 1996) photoreceptor membranes. This suggests that these channels may constitute a common endpoint in phototransduction pathways.…”

Section: Discussionmentioning

confidence: 99%

2-Aminoethoxydiphenylborane Is an Acute Inhibitor of Directly Photosensitive Retinal Ganglion Cell ActivityIn VitroandIn Vivo

Sekaran¹,

Lall²,

Ralphs³

et al. 2007

J. Neurosci.

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The mammalian retina contains directly photosensitive retinal ganglion cells (RGCs), which use the photopigment melanopsin. The generation of mice lacking melanopsin has been invaluable in elucidating the function of these cells. These animals display deficiencies in circadian photoentrainment, the pupil light reflex, and the circadian regulation of the cone pathway. Interpreting the results from such gene knock-out models is always complicated by neuronal plasticity and the potential for restructuring of neuronal networks. Until now, the study of photosensitive RGCs has lacked an acute inhibitor. 2-Aminoethoxydiphenylborane (2-APB) is an antagonist at IP 3 receptors and an inhibitor of canonical transient receptor potential ion channels (TRPCs). Here, we show that 2-APB is an extremely potent in vitro inhibitor of the photosensitive RGCs and that its effect is independent of store-dependent Ca 2ϩ release. The identification of canonical TRPC6 and TRPC7 ion channels in melanopsin-expressing ganglion cells suggests that 2-APB may act directly on a TRPC ion channel. Importantly, using the pupil light reflex as a functional assay, we show that 2-APB inhibits photosensitive RGC activity in vivo. Collectively, our data further elucidate the phototransduction pathway in the photosensitive RGCs and demonstrate that 2-APB can be used to silence activity in these cells both in vitro and in vivo.

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Section: Discussionmentioning

confidence: 99%

2-Aminoethoxydiphenylborane Is an Acute Inhibitor of Directly Photosensitive Retinal Ganglion Cell ActivityIn VitroandIn Vivo

Sekaran¹,

Lall²,

Ralphs³

et al. 2007

J. Neurosci.

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“…sTRP from D. pealeii had not been sequenced prior to this search (accession number KR107045). Primers used to identify sTRP in D. pealeii were designed using the sequence from Loligo forbesi (Monk et al, 1996). The partial sTRP sequence (216 amino acids) identified in D. pealeii differs by one amino acid from the sequence identified in L. forbesi (Monk et al, 1996).…”

Section: G Qαmentioning

confidence: 99%

“…Primers used to identify sTRP in D. pealeii were designed using the sequence from Loligo forbesi (Monk et al, 1996). The partial sTRP sequence (216 amino acids) identified in D. pealeii differs by one amino acid from the sequence identified in L. forbesi (Monk et al, 1996). While sTRP is thought to function as the ion channel involved in retinal phototransduction in cephalopods, this has not been empirically confirmed (Monk et al, 1996).…”

Section: G Qαmentioning

confidence: 99%

“…Dissociation of the heterotrimeric G-protein signals a downstream cascade, which involves phospholipase C (PLC) and the second messengers inositol triphosphate (IP3) and diacylglycerol (DAG) (Arendt, 2003). This cascade ultimately leads to the opening of ion channels, which are thought to be a type of TRP channel called squid transient receptor potential channel (sTRP) (Monk et al, 1996), thereby initiating a cellular signal. The presence of these signaling molecules as well as retinal opsin, indicates that a particular cell type may function in photoreception.…”

Section: Introductionmentioning

confidence: 99%

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Visual phototransduction components in cephalopod chromatophores suggest dermal photoreception

Kingston

Kuzirian

Hanlon

et al. 2015

Journal of Experimental Biology

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Cephalopod mollusks are renowned for their colorful and dynamic body patterns, produced by an assemblage of skin components that interact with light. These may include iridophores, leucophores, chromatophores and (in some species) photophores. Here, we present molecular evidence suggesting that cephalopod chromatophores -small dermal pigmentary organs that reflect various colors of light -are photosensitive. RT-PCR revealed the presence of transcripts encoding rhodopsin and retinochrome within the retinas and skin of the squid Doryteuthis pealeii, and the cuttlefish Sepia officinalis and Sepia latimanus. In D. pealeii, G qα and squid TRP channel transcripts were present in the retina and in all dermal samples. Rhodopsin, retinochrome and G qα transcripts were also found in RNA extracts from dissociated chromatophores isolated from D. pealeii dermal tissues. Immunohistochemical staining labeled rhodopsin, retinochrome and G qα proteins in several chromatophore components, including pigment cell membranes, radial muscle fibers, and sheath cells. This is the first evidence that cephalopod dermal tissues, and specifically chromatophores, may possess the requisite combination of molecules required to respond to light.

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“…It is possible that the presence of a Pro instead of a Leu in this position may affect the structure of the hTRP7 N-terminal region and influence both the interaction of the channel with the cytoskeleton and the function of the channel itself (53,55,(57)(58)(59)(60). Future studies using mutagenesis, functional analysis, and yeast two-hybrid screening will help to address the importance of this amino acid substitution.…”

Section: Htrp7 Is a Store-operated Cation Channelmentioning

confidence: 99%

Cloning and Functional Expression of Human Short TRP7, a Candidate Protein for Store-operated Ca2+ Influx

Riccio¹,

Mattei²,

Kelsell

et al. 2002

Journal of Biological Chemistry

111

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The regulation and control of plasma membrane Ca 2؉ fluxes is critical for the initiation and maintenance of a variety of signal transduction cascades. Recently, the study of transient receptor potential channels (TRPs) has suggested that these proteins have an important role to play in mediating capacitative calcium entry. In this study, we have isolated a cDNA from human brain that encodes a novel transient receptor potential channel termed human TRP7 (hTRP7). hTRP7 is a member of the short TRP channel family and is 98% homologous to mouse TRP7 (mTRP7). At the mRNA level hTRP7 was widely expressed in tissues of the central nervous system, as well as some peripheral tissues such as pituitary gland and kidney. However, in contrast to mTRP7, which is highly expressed in heart and lung, hTRP7 was undetectable in these tissues. For functional analysis, we heterologously expressed hTRP7 cDNA in an human embryonic kidney cell line. In comparison with untransfected cells depletion of intracellular calcium stores in hTRP7-expressing cells, using either carbachol or thapsigargin, produced a marked increase in the subsequent level of Ca 2؉ influx. This increased Ca 2؉ entry was blocked by inhibitors of capacitative calcium entry such as La 3؉ and Gd 3؉ . Furthermore, transient transfection of an hTRP7 antisense expression construct into cells expressing hTRP7 eliminated the augmented store-operated Ca 2؉ entry. Our findings suggest that hTRP7 is a store-operated calcium channel, a finding in stark contrast to the mouse orthologue, mTRP7, which is reported to enhance Ca 2؉ influx independently of store depletion, and suggests that human and mouse TRP7 channels may fulfil different physiological roles.

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Isolation, Cloning, and Characterisation of a trp Homologue from Squid (Loligo forbesi) Photoreceptor Membranes

Cited by 29 publications

References 29 publications

2-Aminoethoxydiphenylborane Is an Acute Inhibitor of Directly Photosensitive Retinal Ganglion Cell ActivityIn VitroandIn Vivo

2-Aminoethoxydiphenylborane Is an Acute Inhibitor of Directly Photosensitive Retinal Ganglion Cell ActivityIn VitroandIn Vivo

Visual phototransduction components in cephalopod chromatophores suggest dermal photoreception

Cloning and Functional Expression of Human Short TRP7, a Candidate Protein for Store-operated Ca2+ Influx

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