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J Cell Biol. 1987 Dec 1; 105(6): 2723–2733.
PMCID: PMC2114723

Acidification of morphologically distinct endosomes in mutant and wild- type Chinese hamster ovary cells


In the preceding paper (Yamashiro, D. J., and F. R. Maxfield. 1987. J. Cell Biol. 105:2713-2721), we have shown that there is rapid acidification of endosomal compartments to pH 6.3 by 3 min in wild-type Chinese hamster ovary (CHO) cells. In contrast, early acidification of endosomes is markedly reduced in the CHO mutants, DTF 1-5-4 and DTF 1-5- 1. Since these CHO mutants are pleiotropically defective in endocytosis (Robbins, A. R., S. S. Peng, and J. L. Marshall. 1983. J. Cell Biol. 96:1064-1071; Robbins, A. R., C. Oliver, J. L. Bateman, S. S. Krag, C. J. Galloway, and I. Mellman. 1984. J. Cell Biol. 99:1296-1308), our results are consistent with a requirement for proper acidification of early endocytic compartments in many pH-regulated endocytic processes. In this paper, by measuring the pH of morphologically distinct endosomes using fluorescence microscopy and digital image analysis, we have determined in which of the endocytic compartments the defective acidification occurs. We found that the acidification of both the para- Golgi recycling endosomes and lysosomes was normal in the CHO mutants DTG 1-5-4 and DTF 1-5-1. The mean pH of large endosomes containing either fluorescein-labeled alpha 2-macroglobulin or fluorescein- isothiocyanate dextran was only slightly less acidic in the mutant cells than in wild-type cells. However, when we examined the pH of individual large (150-250 nm) endosomes, we found that there was an increased number of endosomes with a pH greater than 6.5 in the CHO mutants when compared with wild-type cells. Heterogeneity in the acidification of large endosomes was also seen in DTF 1-5-1 by a combined null point pH method and digital image analysis technique. In addition, both CHO mutants showed a marked decrease in the acidification of the earliest endosomal compartment, a diffusely fluorescent compartment comprised of small vesicles and tubules. We suggest that the defect in endosome acidification is most pronounced in the early, small vesicular, and tubular endosomes and that this defect partially carries over to the large endosomes that are involved in the sorting and processing of ligands. The proper step-wise acidification of the different endosomes along the endocytic pathway may have an important role in the regulation of endocytic processes.

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Selected References

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  • Basu SK, Goldstein JL, Brown MS. Characterization of the low density lipoprotein receptor in membranes prepared from human fibroblasts. J Biol Chem. 1978 Jun 10;253(11):3852–3856. [PubMed]
  • Brown MS, Anderson RG, Goldstein JL. Recycling receptors: the round-trip itinerary of migrant membrane proteins. Cell. 1983 Mar;32(3):663–667. [PubMed]
  • Dautry-Varsat A, Ciechanover A, Lodish HF. pH and the recycling of transferrin during receptor-mediated endocytosis. Proc Natl Acad Sci U S A. 1983 Apr;80(8):2258–2262. [PMC free article] [PubMed]
  • Dorland RB, Middlebrook JL, Leppla SH. Receptor-mediated internalization and degradation of diphtheria toxin by monkey kidney cells. J Biol Chem. 1979 Nov 25;254(22):11337–11342. [PubMed]
  • Draper RK, Simon MI. The entry of diphtheria toxin into the mammalian cell cytoplasm: evidence for lysosomal involvement. J Cell Biol. 1980 Dec;87(3 Pt 1):849–854. [PMC free article] [PubMed]
  • Geuze HJ, Slot JW, Strous GJ, Lodish HF, Schwartz AL. Intracellular site of asialoglycoprotein receptor-ligand uncoupling: double-label immunoelectron microscopy during receptor-mediated endocytosis. Cell. 1983 Jan;32(1):277–287. [PubMed]
  • Geuze HJ, Slot JW, Schwartz AL. Membranes of sorting organelles display lateral heterogeneity in receptor distribution. J Cell Biol. 1987 Jun;104(6):1715–1723. [PMC free article] [PubMed]
  • Gonzalez-Noriega A, Grubb JH, Talkad V, Sly WS. Chloroquine inhibits lysosomal enzyme pinocytosis and enhances lysosomal enzyme secretion by impairing receptor recycling. J Cell Biol. 1980 Jun;85(3):839–852. [PMC free article] [PubMed]
  • Horwitz MA, Maxfield FR. Legionella pneumophila inhibits acidification of its phagosome in human monocytes. J Cell Biol. 1984 Dec;99(6):1936–1943. [PMC free article] [PubMed]
  • Hudson TH, Neville DM., Jr Quantal entry of diphtheria toxin to the cytosol. J Biol Chem. 1985 Mar 10;260(5):2675–2680. [PubMed]
  • Kielian MC, Marsh M, Helenius A. Kinetics of endosome acidification detected by mutant and wild-type Semliki Forest virus. EMBO J. 1986 Dec 1;5(12):3103–3109. [PMC free article] [PubMed]
  • Klausner RD, van Renswoude J, Kempf C, Rao K, Bateman JL, Robbins AR. Failure to release iron from transferrin in a Chinese hamster ovary cell mutant pleiotropically defective in endocytosis. J Cell Biol. 1984 Mar;98(3):1098–1101. [PMC free article] [PubMed]
  • Leroy JG, Ho MW, MacBrinn MC, Zielke K, Jacob J, O'Brien JS. I-cell disease: biochemical studies. Pediatr Res. 1972 Oct;6(10):752–757. [PubMed]
  • Lestas AN. The effect of pH upon human transferrin: selective labelling of the two iron-binding sites. Br J Haematol. 1976 Mar;32(3):341–350. [PubMed]
  • Marsh M, Bolzau E, Helenius A. Penetration of Semliki Forest virus from acidic prelysosomal vacuoles. Cell. 1983 Mar;32(3):931–940. [PubMed]
  • Maxfield FR. Weak bases and ionophores rapidly and reversibly raise the pH of endocytic vesicles in cultured mouse fibroblasts. J Cell Biol. 1982 Nov;95(2 Pt 1):676–681. [PMC free article] [PubMed]
  • McGraw TE, Greenfield L, Maxfield FR. Functional expression of the human transferrin receptor cDNA in Chinese hamster ovary cells deficient in endogenous transferrin receptor. J Cell Biol. 1987 Jul;105(1):207–214. [PMC free article] [PubMed]
  • Mellman I, Fuchs R, Helenius A. Acidification of the endocytic and exocytic pathways. Annu Rev Biochem. 1986;55:663–700. [PubMed]
  • Mueller SC, Hubbard AL. Receptor-mediated endocytosis of asialoglycoproteins by rat hepatocytes: receptor-positive and receptor-negative endosomes. J Cell Biol. 1986 Mar;102(3):932–942. [PMC free article] [PubMed]
  • Poole B, Ohkuma S. Effect of weak bases on the intralysosomal pH in mouse peritoneal macrophages. J Cell Biol. 1981 Sep;90(3):665–669. [PMC free article] [PubMed]
  • Princiotto JV, Zapolski EJ. Difference between the two iron-binding sites of transferrin. Nature. 1975 May 1;255(5503):87–88. [PubMed]
  • Robbins AR, Peng SS, Marshall JL. Mutant Chinese hamster ovary cells pleiotropically defective in receptor-mediated endocytosis. J Cell Biol. 1983 Apr;96(4):1064–1071. [PMC free article] [PubMed]
  • Robbins AR, Oliver C, Bateman JL, Krag SS, Galloway CJ, Mellman I. A single mutation in Chinese hamster ovary cells impairs both Golgi and endosomal functions. J Cell Biol. 1984 Oct;99(4 Pt 1):1296–1308. [PMC free article] [PubMed]
  • Roederer M, Bowser R, Murphy RF. Kinetics and temperature dependence of exposure of endocytosed material to proteolytic enzymes and low pH: evidence for a maturation model for the formation of lysosomes. J Cell Physiol. 1987 May;131(2):200–209. [PubMed]
  • Roff CF, Fuchs R, Mellman I, Robbins AR. Chinese hamster ovary cell mutants with temperature-sensitive defects in endocytosis. I. Loss of function on shifting to the nonpermissive temperature. J Cell Biol. 1986 Dec;103(6 Pt 1):2283–2297. [PMC free article] [PubMed]
  • Sandvig K, Olsnes S. Diphtheria toxin entry into cells is facilitated by low pH. J Cell Biol. 1980 Dec;87(3 Pt 1):828–832. [PMC free article] [PubMed]
  • Sipe DM, Murphy RF. High-resolution kinetics of transferrin acidification in BALB/c 3T3 cells: exposure to pH 6 followed by temperature-sensitive alkalinization during recycling. Proc Natl Acad Sci U S A. 1987 Oct;84(20):7119–7123. [PMC free article] [PubMed]
  • Steinman RM, Mellman IS, Muller WA, Cohn ZA. Endocytosis and the recycling of plasma membrane. J Cell Biol. 1983 Jan;96(1):1–27. [PMC free article] [PubMed]
  • Storrie B, Pool RR, Jr, Sachdeva M, Maurey KM, Oliver C. Evidence for both prelysosomal and lysosomal intermediates in endocytic pathways. J Cell Biol. 1984 Jan;98(1):108–115. [PMC free article] [PubMed]
  • Tanasugarn L, McNeil P, Reynolds GT, Taylor DL. Microspectrofluorometry by digital image processing: measurement of cytoplasmic pH. J Cell Biol. 1984 Feb;98(2):717–724. [PMC free article] [PubMed]
  • Tycko B, Maxfield FR. Rapid acidification of endocytic vesicles containing alpha 2-macroglobulin. Cell. 1982 Mar;28(3):643–651. [PubMed]
  • Tycko B, Keith CH, Maxfield FR. Rapid acidification of endocytic vesicles containing asialoglycoprotein in cells of a human hepatoma line. J Cell Biol. 1983 Dec;97(6):1762–1776. [PMC free article] [PubMed]
  • Wolkoff AW, Klausner RD, Ashwell G, Harford J. Intracellular segregation of asialoglycoproteins and their receptor: a prelysosomal event subsequent to dissociation of the ligand-receptor complex. J Cell Biol. 1984 Feb;98(2):375–381. [PMC free article] [PubMed]
  • Yamashiro DJ, Maxfield FR. Acidification of endocytic compartments and the intracellular pathways of ligands and receptors. J Cell Biochem. 1984;26(4):231–246. [PubMed]
  • Yamashiro DJ, Maxfield FR. Kinetics of endosome acidification in mutant and wild-type Chinese hamster ovary cells. J Cell Biol. 1987 Dec;105(6 Pt 1):2713–2721. [PMC free article] [PubMed]
  • Yamashiro DJ, Tycko B, Fluss SR, Maxfield FR. Segregation of transferrin to a mildly acidic (pH 6.5) para-Golgi compartment in the recycling pathway. Cell. 1984 Jul;37(3):789–800. [PubMed]

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