Advertisement

Regulatory Influences on the Glycosylation of Rhodopsin By Human and Bovine Retinas

  • Edward L. Kean
  • Jermin Ju
  • Naiqian Niu

Abstract

The retina has assembled oligosaccharide chains on rhodopsin that are unlike those found in other asparagine-linked, complex class of glycoproteins in terms of their abridged size and limited number of sugars. We have examined the kinetic properties of two glycosyltransferases of the retina whose action would be required in order to synthesize oligosaccharide chains of rhodopsin which would be similar in structure to those found in other molecules of this type. We have examined the kinetics of N-acetylglucosaminyltrans-ferase II (GlcNAc-transferase II), required for branching, and galactosyltransferase, required for extending the oligosaccharide chain. Golgi-enriched preparations from human retina, bovine retina and rat liver were used as the enzyme sources and rhodopsin, opsin, and the oligosaccharide isolated from rhodopsin used as acceptors. From an evaluation of the Vmax/Km ratios it was observed that bovine and human retinas have very limited abilities compared to the rat liver to carry out the transfer of GlcNAc and galactose to these acceptors. In keeping with the presence of a relatively high concentration of galactosylated isomers found in human rhodopsin, human retinas had up to 13-fold greater activity of galactosyltransferase than did bovine retina. It was also apparent that the glycosyltransferases were not appreciably influenced by the polypeptide portion of the molecule. A further aspect of metabolic regulation was revealed with the observation that galactosylation of rhodopsin blocked the addition of GlcNAc and thus prevented branching of the oligosaccharide chain. It is suggested that these properties contribute to the assembly of the abridged structures that have been observed in the oligosaccharides of rhodopsins of all species thus far examined. The identification of the substrates and products of the reactions was carried out by chromatographic means.

Keywords

Retinitis Pigmentosa Visual Pigment Human Retina Oligosaccharide Chain Bovine Rhodopsin 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Liang, C.-J., Yamashita, K., Muellenberg, C.G., Shichi, H., and Kobata, A. (1979) Structure of the carbohydrate moieties of bovine rhodopsin, J. Biol. Chem. 254: 6414–6418.PubMedGoogle Scholar
  2. 2.
    Fukuda, M.N., Papermaster, D.S., and Hargrave, P.A. (1979). Rhodopsin Carbohydrate. Structure of small oligosaccharides attached at two sites near the NH2 Terminus, J. Biol. Chem. 254: 8201–8207.PubMedGoogle Scholar
  3. 3.
    Duffm, K.L., Lange, G.W., Welply, J.K., Florman, R., O’ Brien, P.J., Dell, A., Reason, A.J., Morris, H.R. and Fliesler, S.J. (1993) Identification and oligosaccharide structure analysis of rhodopsin glycoforms containing galactose and sialic acid, Glycobiol. 3: 365–380.CrossRefGoogle Scholar
  4. 4.
    Fujita, S., Endo, T., Ju, J., Kean, E.L. and Kobata, A. (1994) Structural studies of the N-linked sugar chains of human rhodopsin, Glycobiol. 4: 633–640.CrossRefGoogle Scholar
  5. 5.
    Schachter, H., Narasimhan, S., Gleeson, P., and Vella, G. (1983) Enzymatic control of oligosaccharide branching during synthesis of membrane glycoproteins, GANN Monograph on Cancer Research 29: 177–195.Google Scholar
  6. 6.
    Bendiak, B., and Schachter, H. (1987) (b) Control of Glycoprotein Synthesis, Kinetic mechanism, substrate specificity, and inhibition characteristics of UDP-N-acetylglucosamine: a-D-mannoside β l-2 N-acetylglucosaminyltransferase II from rat liver, J. Biol. Chem. 262: 5784–5790.PubMedGoogle Scholar
  7. 7.
    Kean, E.L., Hara, S., Mizoguchi, A., Matsumoto, A. and Kobata, A. (1983) The enzymatic cleavage of rhodopsin by the retinal pigment epithelium. II. The carbohydrate composition of the glycopeptide cleavage product, Exp. Eye Res. 36: 817–825.PubMedCrossRefGoogle Scholar
  8. 8.
    Kean, E.L. (1969) Sialic acid activating enzyme in ocular tissue, Exp. Eye Res. 8: 44–54.PubMedCrossRefGoogle Scholar
  9. 9.
    Kean, E.L. (1970) Nuclear cytidine 5′-monophosphate synthetase, J. Biol. Chem. 245: 2301–2308.PubMedGoogle Scholar
  10. 10.
    O’ Brien, P.J. and Muellenberg, CG. (1968) Properties of glycosyltransfer enzymes of bovine retina, Biochim. Biophys. Acta 167: 268–273.CrossRefGoogle Scholar
  11. 11.
    Ju, J. and Kean, E.L. (1992) In vitro galactosylation of rhodopsin and opsin: kinetics, properties and characterization, Exp. Eye Res. 55: 589–6047.PubMedCrossRefGoogle Scholar
  12. 12.
    Ju, J. and Kean, E.L. (1994) Retinal GlcNAc-transferases and the glycosylation of rhodopsin, Exp. Eye Res. 59: 565–576.PubMedCrossRefGoogle Scholar
  13. 13.
    Morre’, DJ., Cheetham, R.D., and Nyquist, S.E. (1972). A simplified procedure for isolation of Golgi apparatus from rat liver, Prep. Biochem. 2: 61–69.PubMedGoogle Scholar
  14. 14.
    Plantner, J.J., Le, M.-L., and Kean, E.L. (1991) Enzymatic deglycosylation of bovine rhodopsin, Exp. Eye Res. 53: 269–274.PubMedCrossRefGoogle Scholar
  15. 15.
    Prasad, A.V.K., Plantner, J.J., and Kean, E.L. (1992) Effect of enzymatic deglycosylation on the regenerability of bovine rhodopsin, Exp. Eye Res. 54: 913–920.PubMedCrossRefGoogle Scholar
  16. 16.
    Kean, E.L., Ju, J., and Niu, N. (1995) Galactosylation of rhodopsin by the human retina, Current Eye Res., 14: 413–419.CrossRefGoogle Scholar
  17. 17.
    Shao, M.-C, and Wold, F. (1988) The effect of the protein matrix on glycan processing in glycoproteins, J. Biol. Chem. 263: 5771–5774.PubMedGoogle Scholar
  18. 18.
    Yet, M.-G., Shao, M.-C. and Wold, F. (1988) Effect of the protein matrix on glycan processing in glycoproteins, FASEB J. 2: 22–31.PubMedGoogle Scholar
  19. 19.
    Smith, S.B., St Jules, R.S., and O’ Brien, P.J. (1991) Transient hyperglycosylation of rhodopsin with galactose, Exp. Eye Res. 53: 525–537.PubMedCrossRefGoogle Scholar
  20. 20.
    Taniguchi, T., Adler, A.J., Mizuochi, T., Kochibe, N., and Kobata, A. (1986) The structures of the asparagine-linked sugar chains of bovine interphotoreceptor retinol-binding protein, J. Biol. Chem. 261: 1730–1736.PubMedGoogle Scholar
  21. 21.
    Dryja, T.P., Hahn, L.B., Cowley, G.S., McGee, T.L., and Berson, E.L. (1991) Mutation spectrum of the rhodopsin gene among patients with autosomal dominant retinitis pigmentosa, Proc. Nat’ lAcad. Sci. USA, 88: 9370–9374.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • Edward L. Kean
    • 1
  • Jermin Ju
    • 1
  • Naiqian Niu
    • 1
  1. 1.Department of OphthalmologyCase Western Reserve UniversityClevelandUSA

Personalised recommendations