Hostname: page-component-586b7cd67f-t7czq Total loading time: 0 Render date: 2024-11-29T22:31:45.876Z Has data issue: false hasContentIssue false
  • English
  • Français

Concentrations of phosphatidylinositol 4,5-bisphosphate and inositol 1,4,5-trisphosphate within the distal segment of squid photoreceptors

Published online by Cambridge University Press:  02 June 2009

Ete Z. Szuts
Ete Z. Szuts
Affiliation:
Laboratory of Sensory Physiology, Marine Biological Laboratory, Woods Hole, Department of Physiology, Boston University School of Medicine, Boston
Get access Rights & Permissions [Opens in a new window]

Abstract

Although inositol trisphosphate (InsP3) is a key substance in phototransduction of invertebrate photoreceptors, its intracellular concentration remains unknown. The purpose of this study was to assay its concentration and the concentration of its precursor, phosphatidylinositol bisphosphate (PtdInsP2), within squid photoreceptors. Rhabdomeric membranes were purified and their PtdInsP2 content measured with a phosphate assay after the extracted phospholipids were deacylated and separated by ion-exchange chromatography. At least 75% of the total PtdInsP2 found in the retinal homogenate was associated with the plasma membranes of the rhabdomeric microvilli, where PtdInsP2 was 3.1 ± 0.7% of the total phospholipids, a level comparable to values published for rat brain. In terms of rhodopsin, microvillar membranes contained 3.7 ± 0.9 mol PtdInsP2/mol rho. The InsP3 content of living retinas was measured with a radioreceptor assay. The basal content of dark-adapted retinas was 0.15 ± 0.05 InsP3/rho, equivalent to 30 ± 9 nmol/g tissue that is about twice that of rat brains. Flash illumination (≈lms in duration) that photoactivated 1% of rhodopsin increased the level about fivefold to 0.68 ± 0.22 lnsP3/rho. Corresponding decrease in PtdInsP2 was undetectable as it was within measurement errors. For PtdInsP2, the measured content corresponds to 5.6 ± 1.4 mM within the volume of rhabdomere. Maximal light-induced concentration of InsP3 is calculated to be 1.2 ± 0.4 mM within the cytoplasm of the distal segment. Each photoactivated rhodopsin leads to the formation of 500 InsP3 molecules when measured 15 s after the flash. Thus, high concentration of InsP3 in these cells is primarily due to restricted intracellular volumes rather than to high amplification by the enzyme cascade. The InsP3 concentration within squid photoreceptors is the highest yet reported for any transducing cell and may indicate the involvement of relatively low affinity receptors or channels during invertebrate phototransduction.

Keywords

Intracellular signalingPhototransductionInositol trisphosphatePhosphatidylinositol bisphosphatePhotoreceptor
Type
Research Articles
Information
Visual Neuroscience , Volume 10 , Issue 5 , September 1993 , pp. 921 - 929
Copyright
Copyright © Cambridge University Press 1993

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abdel-Latif, A.A. (1986). Calcium-mobilizing receptors, polyphosphoinositides, and the generation of second messengers. Pharmacological Reviews 38, 227–272.Google ScholarPubMed
Ames, B.N. (1966). Assay of inorganic phosphate, total phosphate, and phosphatases. Methods of Enzymology 8, 115–118.CrossRefGoogle Scholar
Arikawa, K., Hicks, J.L. & Williams, D.S. (1990). Identification of actin filaments in the rhabdomeral microvilli of Drosophila photoreceptors. Journal of Cell Biology 110, 1993–1998.CrossRefGoogle ScholarPubMed
Bloomquist, B.T., Shortridge, R.D., Schneuwly, S., Perdew, M., Montell, C, Steller, H., Rubin, G. & Pak, W.L. (1988). Isolation of a putative phospholipase C gene of Drosophila, norpA, and its role in phototransduction. Cell 54, 723–733.CrossRefGoogle ScholarPubMed
Bredt, D.S., Mourey, R.J. & Snyder, S.H. (1989). A simple, sensitive, and specific radioreceptor assay for inositol 1,4,5-trisphosphate in biological tissues. Biochemical and Biophysical Research Communications 159, 976–982.CrossRefGoogle ScholarPubMed
Brown, J.E. & Rubin, L.J. (1984). A direct demonstration that inositol trisphosphate induces an increase in intracellular calcium in Limulus photoreceptors. Biochemical and Biophysical Research Communications 125, 1137–1142.CrossRefGoogle ScholarPubMed
Brown, J.E., Watkins, D.C. & Malbon, C.C. (1987). Light-induced changes in the content of inositol phosphates in squid (Loligo pealei) retina. Biochemical Journal 247, 293–297.CrossRefGoogle ScholarPubMed
Brown, J.E., Rudnick, M., Letcher, A.J. & Irvine, R.F. (1988). Formation of methylphosphoryl inositol phosphates by extractions that employ methanol. Biochemical Journal 253, 703–710.CrossRefGoogle ScholarPubMed
Brown, J.E., Combs, A., Ackermann, K. & Malbon, C.C. (1991). Light-induced GTPase activity and GTP[γS] binding in squid retinal photoreceptors. Visual Neuroscience 7, 589–595.CrossRefGoogle ScholarPubMed
Challis, R.A.J., Chilvers, E.R., Willcocks, A.L. & Nahorski, S.R. (1990). Heterogeneity of [3H]inositol 1,4,5-trisphosphate binding sites in adrenal-cortical membranes. Biochemical Journal 265, 421–427.CrossRefGoogle Scholar
Cohen, A.I. (1973). An ultrastructural analysis of the photoreceptors of the squid and their synaptic connections. Journal of Comparative Neurology 147, 351–378.CrossRefGoogle ScholarPubMed
Creba, J.A., Downes, C.P., Hawkins, P.T., Brewster, G., Michell, R.H. & Kirk, C. J. (1983). Rapid breakdown of phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate in rat hepatocytes stimulated by vasopressin and other Ca-mobilizing hormones. Biochemical Journal 212, 733–747.CrossRefGoogle Scholar
de Couet, H.G., Stowe, S. & Blest, A.D. (1984). Membrane-associated actin in the rhabdomeral microvilli of crayfish photoreceptors. Journal of Cell Biology 98, 834–846.CrossRefGoogle ScholarPubMed
Fein, A., Payne, R., Corson, D.W., Berridge, M.J. & Irvine, R.F. (1984). Photoreceptor excitation and adaptation by inositol 1,4,5-trisphosphate. Nature (London) 311, 157–160.CrossRefGoogle ScholarPubMed
French, P.J., Bunce, C.M., Stephens, L.R., Lord, J.M., McConnell, F.M., Brown, G., Creba, J.A. & Michell, R.H. (1991). Changes in the levels of inositol lipids and phosphates during the differentiation of HL60 promyelocytic cells towards neutrophils or monocytes. Proceeding of the Royal Society B (London) 245, 193–201.Google ScholarPubMed
Fukami, K., Furuhashi, K., Inagaki, M., Endo, T., Hatano, S. & Takenawa, T. (1992). Requirement of phosphatidylinositol 4,5-bisphosphate for α-actinin function. Nature 359, 150–152.CrossRefGoogle ScholarPubMed
Goldsmith, T.H. & Wehner, R. (1977). Restrictions on rotational and translational diffusion of pigment in the membranes of a rhabdomeric photoreceptor. Journal of General Physiology 70, 453–490.CrossRefGoogle ScholarPubMed
Gumber, S.C & Lowenstein, J.M. (1986). Non-enzymic phosphorylation of polyphosphoinositides and phosphatidic acid is catalysed by bivalent metal ions. Biochemical Journal 235, 617–619.CrossRefGoogle ScholarPubMed
Hagins, W.A. (1972). The visual process: Excitatory mechanisms in the primary receptor cells. Annual Reviews in Biophysics and Bioengineering 1, 131–158.CrossRefGoogle ScholarPubMed
Hubbard, R. & George, R.C.C.St. (1958). The rhodopsin system of the squid. Journal of General Physiology 41, 501–528.CrossRefGoogle ScholarPubMed
Kito, Y., Seki, T. & Hagins, F.M. (1982). Isolation and purification of squid rhabdoms. Methods of Enzymology 81, 43–48.CrossRefGoogle ScholarPubMed
Mayr, G.W. & Thieleczek, R. (1991). Masses of inositol phosphates in resting and tetanically stimulated vertebrate skeletal muscles. Biochemical Journal 280, 631–640.CrossRefGoogle ScholarPubMed
Nishihara, M. & Keenan, R.W. (1985). Inositol phospholipid levels of rat forebrain obtained by freeze-blowing method. Biochimica et Biophysica Acta 835, 415–418.CrossRefGoogle ScholarPubMed
Payne, R., Corson, D.W., Fein, A. & Berridge, M.J. (1986). Excitation and adaptation of Limulus ventral photoreceptors by inositol 1,4,5-trisphosphate result from a rise in intracellular calcium. Journal of General Physiology 88, 127–142.CrossRefGoogle ScholarPubMed
Pottinger, J.D.D., Ryba, N.J.P., Keen, J.N. & Findlay, J.B.C. (1991). The identification and purification of the heterotrimeric GTP-binding protein from squid (Loligo forbesi) photoreceptors. Biochemical Journal 279, 323–326.CrossRefGoogle ScholarPubMed
Robinson, P.R., Wood, S.F., Szuts, E.Z., Fein, A., Hamm, H.E. & Lisman, J.E. (1990). Light-dependent GTP-binding proteins in squid photoreceptors. Biochemical Journal 272, 79–85.CrossRefGoogle ScholarPubMed
Ryu, S.H., Cho, K.S., Lee, K.-Y., Suh, P.-G. & Rhee, S.G. (1987). Purification and characterization of two immunologically distinct phosphoinositide-specific phospholipase C from bovine brain. Journal of Biological Chemistry 262, 12511–12518.CrossRefGoogle ScholarPubMed
Saibil, H.R. (1982). An ordered membrane-cytoskeleton network in squid photoreceptor microvilli. Journal of Molecular Biology 158, 435–456.CrossRefGoogle ScholarPubMed
Saibil, H.R. (1990). Structure and function of the squid eye. In Squid as Experimental Animals, ed., Gilbert, D.L., Adelman, W.J. & Arnold, J.M. pp. 235–302. New York and London: Plenum Press.Google Scholar
Schneuwly, S., Burg, M.G., Lending, C, Perdew, M.H. & Pak, W.L. (1991). Properties of photoreceptor-specific phospholipase C encoded by the norpA gene of Drosophila melanogaster. Journal of Biological Chemistry 266, 24314–24319.CrossRefGoogle ScholarPubMed
Shortrtdge, R.D. & Pak, W.L. (1991). Inositol phospholipid and invertebrate photoreceptors. Photochemistry and Photobiology 53, 871–875.Google Scholar
Szuts, E.Z. (1992). Squid photoreceptors and retinas: Content of phosphatidylinositol-bisphosphate and inositol trisphosphate. Biological Bulletin 183, 352.CrossRefGoogle ScholarPubMed
Szuts, E.Z., Wood, S.F., Reid, M.S. & Fein, A. (1986). Light stimulates the rapid formation of inositol trisphosphate in squid retinas. Biochemical Journal 240, 929–932.CrossRefGoogle ScholarPubMed
Takenawa, T., Homma, Y. & Emori, Y. (1991). Properties of phospholipase C isozymes. Methods of Enzymology 197, 511–518.CrossRefGoogle ScholarPubMed
Toyoshima, S., Matsumoto, N., Wang, P., Inoue, H., Yoshioka, T., Hotta, Y. & Osawa, R. (1990). Purification and partial amino acid sequences of phosphoinositide-specific phospholipase C of Drosophila eye. Journal of Biological Chemistry 265, 14842–14848.CrossRefGoogle ScholarPubMed
Tsukita, S., Tsukita, S. & Matsumoto, G. (1988). Light-induced structural changes of cytoskeleton in squid photoreceptor microvilli detected by rapid-freeze method. Journal of Cell Biology 106, 1151–1160.CrossRefGoogle ScholarPubMed
Walrond, J.P. & Szuts, E.Z. (1992). Submicrovillar tubules in distal segments of squid photoreceptors detected by rapid freezing. Journal of Neuroscience 12, 1490–1501.CrossRefGoogle ScholarPubMed
Wood, S.F., Szuts, E.Z. & Fein, A. (1989). Inositol trisphosphate production in squid photoreceptors: Activation by light, aluminum fluoride, and guanine nucleotides. Journal of Biological Chemistry 264, 12970–12976.CrossRefGoogle ScholarPubMed