Rapid Coupling of Calcium Release to Depolarization in<i>Limulus polyphemus</i>Ventral Photoreceptors as Revealed by Microphotolysis and Confocal Microscopy

Ukhanov, Kirill; Payne, Richard

doi:10.1523/jneurosci.17-05-01701.1997

Cited by 20 publications

(9 citation statements)

References 41 publications

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“…44,124). The main evidence includes direct measurements of light-induced Ca 2ϩ release coincident with, or a few milliseconds before the light-induced current (189), the ability of both InsP 3 and Ca 2ϩ to excite the light-sensitive channels (23,135,136) and the inhibition of the light response by Ca 2ϩ chelators (171). However, in Drosophila, but not in the large flies (41), InsP 3 and Ca 2ϩ failed to excite the photoreceptor cells (57,153).…”

Section: B Activation Of Trp and Trpl Channelsmentioning

confidence: 99%

TRP Channel Proteins and Signal Transduction

Minke

Cook

2002

Physiological Reviews

530

519

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TRP channel proteins constitute a large and diverse family of proteins that are expressed in many tissues and cell types. This family was designated TRP because of a spontaneously occurring Drosophila mutant lacking TRP that responded to a continuous light with a transient receptor potential (hence TRP). In addition to responses to light, TRPs mediate responses to nerve growth factor, pheromones, olfaction, mechanical, chemical, temperature, pH, osmolarity, vasorelaxation of blood vessels, and metabolic stress. Furthermore, mutations in several members of TRP-related channel proteins are responsible for several diseases, such as several tumors and neurodegenerative disorders. TRP-related channel proteins are found in a variety of organisms, tissues, and cell types, including nonexcitable, smooth muscle, and neuronal cells. The large functional diversity of TRPs is also reflected in their diverse permeability to ions, although, in general, they are classified as nonselective cationic channels. The molecular domains that are conserved in all members of the TRP family constitute parts of the transmembrane domains and in most members also the ankyrin-like repeats at the NH2 terminal of the protein and a "TRP domain" at the COOH terminal, which is a highly conserved 25-amino acid stretch with still unknown function. All of the above features suggest that members of the TRP family are "special assignment" channels, which are recruited to diverse signaling pathways. The channels' roles and characteristics such as gating mechanism, regulation, and permeability are determined by evolution according to the specific functional requirements.

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Section: B Activation Of Trp and Trpl Channelsmentioning

confidence: 99%

TRP Channel Proteins and Signal Transduction

Minke

Cook

2002

Physiological Reviews

530

519

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“…There has been previous speculation that the light-dependent channels may not be uniformly positioned over the microvilli, but selectively positioned at their base. The localization of the putative channels at the base of the rhabdomere may be important for efficient coupling of the putative channel to the release of Ca 2ϩ from intracellular stores below the rhabdom (Payne & Fein, 1987;Bacigalupo & Johnson, 1992;Shin et al, 1993;Ukhanov & Payne, 1997). In any case, it is clear that EM localization will be required to distinguish among these alternatives.…”

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confidence: 99%

A cGMP-gated channel subunit in Limulus photoreceptors

Chen

Baumann²,

Payne³

et al. 2001

Vis Neurosci

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The phototransduction cascade in invertebrate photoreceptors has not been fully elucidated. It has been proposed that in Limulus ventral photoreceptor cGMP is the intracellular second messenger that directly controls the gating of the light-dependent channels (Johnson et al., 1986: Bacigalupo et al., 1991). Recently, a putative cGMP-gated channel cDNA, Lcng1, has been cloned from Limulus and shown to be expressed in the brain and the ventral eye (Chen et al., 1999). In this study, we sought to more specifically localize the LCNG1 transcript and protein. In situ hybridization was used to determine whether the gene is expressed in glia or photoreceptor cells in the ventral eye. The results clearly demonstrated that Lcngl mRNA is transcribed in the ventral photoreceptors. On Western blots probed with a polyclonal antibody raised against the C-terminus of LCNGI, a 100-kDa band and an 80-kDa band was labeled in the membrane protein preparations from brain and ventral eye, respectively. The labeling of these bands was blocked by preabsorption of the antibody with the antigen, indicating the labeling specificity. Immunocytochemistry and confocal microscopy were applied to investigate the subcellular localization of this antigen. Immunolabeling was highly localized in the transducing lobes of ventral eye photoreceptors and lateral eye photoreceptors. In both cases, the labeling was associated with membrane regions specialized for phototransduction, but the exact pattern appeared to be somewhat different in the two eyes. Preabsorption of the antiserum with antigen abolished the labeling, confirming specificity. The results lend support to the hypothesis that a cGMP-gated channel is directly involved in the phototransduction process.

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“…(g) Rapid release of calcium by flash photolysis of caged calcium activates an inward current within a few milliseconds ( Ukhanov and Payne, 1997 ).…”

Section: Discussionmentioning

confidence: 99%

Inositol 1,4,5-trisphosphate–induced Calcium Release Is Necessary for Generating the Entire Light Response of Limulus Ventral Photoreceptors

Fein

2003

The Journal of General Physiology

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The experiments reported here were designed to answer the question of whether inositol 1,4,5-trisphosphate (IP3)-induced calcium release is necessary for generating the entire light response of Limulus ventral photoreceptors. For this purpose the membrane-permeable IP3 receptor antagonist 2-aminoethoxydiphenyl borate (2APB) (Maruyama, T., T. Kanaji, S. Nakade, T. Kanno, and K. Mikoshiba. 1997. J. Biochem. (Tokyo). 122:498–505) was used. Previously, 2APB was found to inhibit the light activated current of Limulus ventral photoreceptors and reversibly inhibit both light and IP3 induced calcium release as well as the current activated by pressure injection of calcium into the light sensitive lobe of the photoreceptor (Wang, Y., M. Deshpande, and R. Payne. 2002. Cell Calcium. 32:209). In this study 2APB was found to inhibit the response to a flash of light at all light intensities and to inhibit the entire light response to a step of light, that is, both the initial transient and the steady-state components of the response to a step of light were inhibited. The light response in cells injected with the calcium buffer 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) was reversibly inhibited by 2APB, indicating that these light responses result from IP3-mediated calcium release giving rise to an increase in Cai. The light response obtained from cells after treatment with 100 μM cyclopiazonic acid (CPA), which acts to empty intracellular calcium stores, was reversibly inhibited by 2APB, indicating that the light response after CPA treatment results from IP3-mediated calcium release and a consequent rise in Cai. Together these findings imply that IP3-induced calcium release is necessary for generating the entire light response of Limulus ventral photoreceptors.

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Rapid Coupling of Calcium Release to Depolarization inLimulus polyphemusVentral Photoreceptors as Revealed by Microphotolysis and Confocal Microscopy

Cited by 20 publications

References 41 publications

TRP Channel Proteins and Signal Transduction

TRP Channel Proteins and Signal Transduction

A cGMP-gated channel subunit in Limulus photoreceptors

Inositol 1,4,5-trisphosphate–induced Calcium Release Is Necessary for Generating the Entire Light Response of Limulus Ventral Photoreceptors

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