Abstract
Adsorptive pinocytosis of acid hydrolases by fibroblasts depends on phosphomannosyl recognition markers on the enzymes and high-affinity pinocytosis receptors on the cell surface. In this study, beta- glucuronidase binding to the cell surface of attached fibroblasts was found to be saturable and inhibitable by mannose-6-phosphate (Man-6-P). Dissociation of cell-bound beta-glucuronidase occurred very slowly at neutral pH, but was greatly accelerated by lowering the pH below 6.0, or by exposure to Man-6-P. Comparison of the maximal cell surface binding and the observed rate of enzyme pinocytosis suggests that the pinocytosis receptors are replaced or reused about every 5 min. Enzyme pinocytosis was not affected by inhibition of new protein synthesis for several hours, suggesting a large pool of internal receptors and/or reuse of internalized receptors. Chloroquine treatment of normal human fibroblasts had three effects: (a) greatly enhanced secretion of newly synthesized acid hydrolases bearing the recognition marker for uptake, (b) depletion of enzyme-binding sites from the cell surface, and (c) inhibition of pinocytosis of exogenous enzyme. Only the third effect was seen in I-cell disease fibroblasts, which were also less sensitive than control cells to this effect. These observations are consistent with a model for transport of acid hydrolases that proposes that delivery of newly synthesized acid hydrolases to lysosomes requires the phosphomannosyl recognition marker on the enzymes, and intracellular receptors that segregate receptor-bound enzymes into vesicles for transport to lysosomes. This model explains how chloroquine, which raises intralysosomal pH, can disrupt both the intracellular pathway for newly synthesized acid hydrolases, and the one for uptake of exogenous enzyme by cell surface pinocytosis receptors.
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- Distler J., Hieber V., Sahagian G., Schmickel R., Jourdian G. W. Identification of mannose 6-phosphate in glycoproteins that inhibit the assimilation of beta-galactosidase by fibroblasts. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4235–4239. doi: 10.1073/pnas.76.9.4235. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Friend D. S., Farquhar M. G. Functions of coated vesicles during protein absorption in the rat vas deferens. J Cell Biol. 1967 Nov;35(2):357–376. doi: 10.1083/jcb.35.2.357. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Glaser J. H., Roozen K. J., Brot F. E., Sly W. S. Multiple isoelectric and recognition forms of human beta-glucuronidase activity. Arch Biochem Biophys. 1975 Feb;166(2):536–542. doi: 10.1016/0003-9861(75)90417-8. [DOI] [PubMed] [Google Scholar]
- Glaser J. H., Sly W. S. Beta-glucuronidase deficiency mucopolysaccharidosis: methods for enzymatic diagnosis. J Lab Clin Med. 1973 Dec;82(6):969–977. [PubMed] [Google Scholar]
- Goldstein J. L., Anderson R. G., Brown M. S. Coated pits, coated vesicles, and receptor-mediated endocytosis. Nature. 1979 Jun 21;279(5715):679–685. doi: 10.1038/279679a0. [DOI] [PubMed] [Google Scholar]
- Hickman S., Neufeld E. F. A hypothesis for I-cell disease: defective hydrolases that do not enter lysosomes. Biochem Biophys Res Commun. 1972 Nov 15;49(4):992–999. doi: 10.1016/0006-291x(72)90310-5. [DOI] [PubMed] [Google Scholar]
- Kaplan A., Achord D. T., Sly W. S. Phosphohexosyl components of a lysosomal enzyme are recognized by pinocytosis receptors on human fibroblasts. Proc Natl Acad Sci U S A. 1977 May;74(5):2026–2030. doi: 10.1073/pnas.74.5.2026. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kaplan A., Fischer D., Achord D., Sly W. Phosphohexosyl recognition is a general characteristic of pinocytosis of lysosomal glycosidases by human fibroblasts. J Clin Invest. 1977 Nov;60(5):1088–1093. doi: 10.1172/JCI108860. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Natowicz M. R., Chi M. M., Lowry O. H., Sly W. S. Enzymatic identification of mannose 6-phosphate on the recognition marker for receptor-mediated pinocytosis of beta-glucuronidase by human fibroblasts. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4322–4326. doi: 10.1073/pnas.76.9.4322. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Neufeld E. F., Lim T. W., Shapiro L. J. Inherited disorders of lysosomal metabolism. Annu Rev Biochem. 1975;44:357–376. doi: 10.1146/annurev.bi.44.070175.002041. [DOI] [PubMed] [Google Scholar]
- Neufeld E. F., Sando G. N., Garvin A. J., Rome L. H. The transport of lysosomal enzymes. J Supramol Struct. 1977;6(1):95–101. doi: 10.1002/jss.400060108. [DOI] [PubMed] [Google Scholar]
- Nicol D. M., Lagunoff D., Pritzl P. Differential uptake of human beta-glucuronidase isoenzymes from spleen by deficient fibroblasts. Biochem Biophys Res Commun. 1974 Aug 5;59(3):941–946. doi: 10.1016/s0006-291x(74)80070-7. [DOI] [PubMed] [Google Scholar]
- Novikoff A. B. The endoplasmic reticulum: a cytochemist's view (a review). Proc Natl Acad Sci U S A. 1976 Aug;73(8):2781–2787. doi: 10.1073/pnas.73.8.2781. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ohkuma S., Poole B. Fluorescence probe measurement of the intralysosomal pH in living cells and the perturbation of pH by various agents. Proc Natl Acad Sci U S A. 1978 Jul;75(7):3327–3331. doi: 10.1073/pnas.75.7.3327. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rome L. H., Weissmann B., Neufeld E. F. Direct demonstration of binding of a lysosomal enzyme, alpha-L-iduronidase, to receptors on cultured fibroblasts. Proc Natl Acad Sci U S A. 1979 May;76(5):2331–2334. doi: 10.1073/pnas.76.5.2331. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sando G. N., Neufeld E. F. Recognition and receptor-mediated uptake of a lysosomal enzyme, alpha-l-iduronidase, by cultured human fibroblasts. Cell. 1977 Nov;12(3):619–627. doi: 10.1016/0092-8674(77)90262-8. [DOI] [PubMed] [Google Scholar]
- Sando G. N., Titus-Dillon P., Hall C. W., Neufeld E. F. Inhibition of receptor-mediated uptake of a lysosomal enzyme into fibroblasts by chloroquine, procaine and ammonia. Exp Cell Res. 1979 Mar 15;119(2):359–364. doi: 10.1016/0014-4827(79)90364-1. [DOI] [PubMed] [Google Scholar]
- Skudlarek M. D., Swank R. T. Biosynthesis of two lysosomal enzymes in macrophages. Evidence for a precursor of beta-galactosidase. J Biol Chem. 1979 Oct 25;254(20):9939–9942. [PubMed] [Google Scholar]
- Steinman R. M., Silver J. M., Cohn Z. A. Pinocytosis in fibroblasts. Quantitative studies in vitro. J Cell Biol. 1974 Dec;63(3):949–969. doi: 10.1083/jcb.63.3.949. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ullrich K., Mersmann G., Weber E., Von Figura K. Evidence for lysosomal enzyme recognition by human fibroblasts via a phosphorylated carbohydrate moiety. Biochem J. 1978 Mar 15;170(3):643–650. doi: 10.1042/bj1700643. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vladutiu G. D., Rattazzi M. C. Excretion-reuptake route of beta-hexosaminidase in normal and I-cell disease cultured fibroblasts. J Clin Invest. 1979 Apr;63(4):595–601. doi: 10.1172/JCI109341. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Von Figura K., Voss B. Cell surface-associated lysosomal enzymes in cultured human skin fibroblasts. Exp Cell Res. 1979 Jul;121(2):267–276. doi: 10.1016/0014-4827(79)90004-1. [DOI] [PubMed] [Google Scholar]
- Wiesmann U. N., DiDonato S., Herschkowitz N. N. Effect of chloroquine on cultured fibroblasts: release of lysosomal hydrolases and inhibition of their uptake. Biochem Biophys Res Commun. 1975 Oct 27;66(4):1338–1343. doi: 10.1016/0006-291x(75)90506-9. [DOI] [PubMed] [Google Scholar]
- von Figura K., Klein U. Isolation and characterization of phosphorylated oligosaccharides from alpha-N-acetylglucosaminidase that are recognized by cell-surface receptors. Eur J Biochem. 1979 Mar;94(2):347–354. doi: 10.1111/j.1432-1033.1979.tb12900.x. [DOI] [PubMed] [Google Scholar]
- von Figura K., Kresse H. Quantitative aspects of pinocytosis and the intracellular fate of N-acetyl-alpha-D-glucosaminidase in Sanfilippo B fibroblasts. J Clin Invest. 1974 Jan;53(1):85–90. doi: 10.1172/JCI107563. [DOI] [PMC free article] [PubMed] [Google Scholar]
- von Figura K., Weber E. An alternative hypothesis of cellular transport of lysosomal enzymes in fibroblasts. Effect of inhibitors of lysosomal enzyme endocytosis on intra- and extra-cellular lysosomal enzyme activities. Biochem J. 1978 Dec 15;176(3):943–950. doi: 10.1042/bj1760943. [DOI] [PMC free article] [PubMed] [Google Scholar]