Abstract
Cellular homeostasis in neurons requires that the synthesis and anterograde axonal transport of protein and membrane be balanced by their degradation and retrograde transport. To address the nature and regulation of retrograde transport in cultured sympathetic neurons, I analyzed the behavior, composition, and ultrastructure of a class of large, phase-dense organelles whose movement has been shown to be influenced by axonal growth (Hollenbeck, P. J., and D. Bray. 1987. J. Cell Biol. 105:2827-2835). In actively elongating axons these organelles underwent both anterograde and retrograde movements, giving rise to inefficient net retrograde transport. This could be shifted to more efficient, higher volume retrograde transport by halting axonal outgrowth, or conversely shifted to less efficient retrograde transport with a larger anterograde component by increasing the intracellular cyclic AMP concentration. When neurons were loaded with Texas red- dextran by trituration, autophagy cleared the label from an even distribution throughout the neuronal cytosol to a punctate, presumably lysosomal, distribution in the cell body within 72 h. During this process, 100% of the phase-dense organelles were fluorescent, showing that they contained material sequestered from the cytosol and indicating that they conveyed this material to the cell body. When 29 examples of this class of organelle were identified by light microscopy and then relocated using correlative electron microscopy, they had a relatively constant ultrastructure consisting of a bilamellar or multilamellar boundary membrane and cytoplasmic contents, characteristic of autophagic vacuoles. When neurons took up Lucifer yellow, FITC-dextran, or Texas red-ovalbumin from the medium via endocytosis at the growth cone, 100% of the phase-dense organelles became fluorescent, demonstrating that they also contain products of endocytosis. Furthermore, pulse-chase experiments with fluorescent endocytic tracers confirmed that these organelles are formed in the most distal region of the axon and undergo net retrograde transport. Quantitative ratiometric imaging with endocytosed 8-hydroxypyrene-1,3,6- trisulfonic acid showed that the mean pH of their lumena was 7.05. These results indicate that the endocytic and autophagic pathways merge in the distal axon, resulting in a class of predegradative organelles that undergo regulated transport back to the cell body.
Full Text
The Full Text of this article is available as a PDF (2.8 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Allen R. D., Metuzals J., Tasaki I., Brady S. T., Gilbert S. P. Fast axonal transport in squid giant axon. Science. 1982 Dec 10;218(4577):1127–1129. doi: 10.1126/science.6183744. [DOI] [PubMed] [Google Scholar]
- Allen R. D., Weiss D. G., Hayden J. H., Brown D. T., Fujiwake H., Simpson M. Gliding movement of and bidirectional transport along single native microtubules from squid axoplasm: evidence for an active role of microtubules in cytoplasmic transport. J Cell Biol. 1985 May;100(5):1736–1752. doi: 10.1083/jcb.100.5.1736. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Brady S. T. A novel brain ATPase with properties expected for the fast axonal transport motor. Nature. 1985 Sep 5;317(6032):73–75. doi: 10.1038/317073a0. [DOI] [PubMed] [Google Scholar]
- Brady S. T., Lasek R. J., Allen R. D. Fast axonal transport in extruded axoplasm from squid giant axon. Science. 1982 Dec 10;218(4577):1129–1131. doi: 10.1126/science.6183745. [DOI] [PubMed] [Google Scholar]
- Buchner K., Seitz-Tutter D., Schönitzer K., Weiss D. G. A quantitative study of anterograde and retrograde axonal transport of exogenous proteins in olfactory nerve C-fibers. Neuroscience. 1987 Aug;22(2):697–707. doi: 10.1016/0306-4522(87)90366-6. [DOI] [PubMed] [Google Scholar]
- Bunge M. B. Fine structure of nerve fibers and growth cones of isolated sympathetic neurons in culture. J Cell Biol. 1973 Mar;56(3):713–735. doi: 10.1083/jcb.56.3.713. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cassel D., Pfeuffer T. Mechanism of cholera toxin action: covalent modification of the guanyl nucleotide-binding protein of the adenylate cyclase system. Proc Natl Acad Sci U S A. 1978 Jun;75(6):2669–2673. doi: 10.1073/pnas.75.6.2669. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cassel D., Selinger Z. Mechanism of adenylate cyclase activation by cholera toxin: inhibition of GTP hydrolysis at the regulatory site. Proc Natl Acad Sci U S A. 1977 Aug;74(8):3307–3311. doi: 10.1073/pnas.74.8.3307. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cheng T. P., Reese T. S. Polarized compartmentalization of organelles in growth cones from developing optic tectum. J Cell Biol. 1985 Oct;101(4):1473–1480. doi: 10.1083/jcb.101.4.1473. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Cheng T. P., Reese T. S. Recycling of plasmalemma in chick tectal growth cones. J Neurosci. 1987 Jun;7(6):1752–1759. doi: 10.1523/JNEUROSCI.07-06-01752.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Clarke M. S., McNeil P. L. Syringe loading introduces macromolecules into living mammalian cell cytosol. J Cell Sci. 1992 Jul;102(Pt 3):533–541. doi: 10.1242/jcs.102.3.533. [DOI] [PubMed] [Google Scholar]
- Clement N. R., Gould J. M. Pyranine (8-hydroxy-1,3,6-pyrenetrisulfonate) as a probe of internal aqueous hydrogen ion concentration in phospholipid vesicles. Biochemistry. 1981 Mar 17;20(6):1534–1538. doi: 10.1021/bi00509a019. [DOI] [PubMed] [Google Scholar]
- Croall D. E., DeMartino G. N. Calcium-activated neutral protease (calpain) system: structure, function, and regulation. Physiol Rev. 1991 Jul;71(3):813–847. doi: 10.1152/physrev.1991.71.3.813. [DOI] [PubMed] [Google Scholar]
- DiStefano P. S., Friedman B., Radziejewski C., Alexander C., Boland P., Schick C. M., Lindsay R. M., Wiegand S. J. The neurotrophins BDNF, NT-3, and NGF display distinct patterns of retrograde axonal transport in peripheral and central neurons. Neuron. 1992 May;8(5):983–993. doi: 10.1016/0896-6273(92)90213-w. [DOI] [PubMed] [Google Scholar]
- Dice J. F., Terlecky S. R., Chiang H. L., Olson T. S., Isenman L. D., Short-Russell S. R., Freundlieb S., Terlecky L. J. A selective pathway for degradation of cytosolic proteins by lysosomes. Semin Cell Biol. 1990 Dec;1(6):449–455. [PubMed] [Google Scholar]
- Dunn W. A., Jr Studies on the mechanisms of autophagy: formation of the autophagic vacuole. J Cell Biol. 1990 Jun;110(6):1923–1933. doi: 10.1083/jcb.110.6.1923. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dunn W. A., Jr Studies on the mechanisms of autophagy: maturation of the autophagic vacuole. J Cell Biol. 1990 Jun;110(6):1935–1945. doi: 10.1083/jcb.110.6.1935. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fabian R. H. Retrograde axonal transport and transcytosis of immunoglobulins: implications for the pathogenesis of autoimmune motor neuron disease. Adv Neurol. 1991;56:433–444. [PubMed] [Google Scholar]
- Fahim M. A., Lasek R. J., Brady S. T., Hodge A. J. AVEC-DIC and electron microscopic analyses of axonally transported particles in cold-blocked squid giant axons. J Neurocytol. 1985 Oct;14(5):689–704. doi: 10.1007/BF01170822. [DOI] [PubMed] [Google Scholar]
- Furukawa R., Wampler J. E., Fechheimer M. Cytoplasmic pH of Dictyostelium discoideum amebae during early development: identification of two cell subpopulations before the aggregation stage. J Cell Biol. 1990 Jun;110(6):1947–1954. doi: 10.1083/jcb.110.6.1947. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Furukawa R., Wampler J. E., Fechheimer M. Measurement of the cytoplasmic pH of Dictyostelium discoideum using a low light level microspectrofluorometer. J Cell Biol. 1988 Dec;107(6 Pt 2):2541–2549. doi: 10.1083/jcb.107.6.2541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gill D. M., Meren R. ADP-ribosylation of membrane proteins catalyzed by cholera toxin: basis of the activation of adenylate cyclase. Proc Natl Acad Sci U S A. 1978 Jul;75(7):3050–3054. doi: 10.1073/pnas.75.7.3050. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Giuliano K. A., Gillies R. J. Determination of intracellular pH of BALB/c-3T3 cells using the fluorescence of pyranine. Anal Biochem. 1987 Dec;167(2):362–371. doi: 10.1016/0003-2697(87)90178-3. [DOI] [PubMed] [Google Scholar]
- Goldberg A. L. The mechanism and functions of ATP-dependent proteases in bacterial and animal cells. Eur J Biochem. 1992 Jan 15;203(1-2):9–23. doi: 10.1111/j.1432-1033.1992.tb19822.x. [DOI] [PubMed] [Google Scholar]
- Gordon P. B., Høyvik H., Seglen P. O. Prelysosomal and lysosomal connections between autophagy and endocytosis. Biochem J. 1992 Apr 15;283(Pt 2):361–369. doi: 10.1042/bj2830361. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gordon P. B., Kovacs A. L., Seglen P. O. Temperature dependence of protein degradation, autophagic sequestration and mitochondrial sugar uptake in rat hepatocytes. Biochim Biophys Acta. 1987 Jul 6;929(2):128–133. doi: 10.1016/0167-4889(87)90167-4. [DOI] [PubMed] [Google Scholar]
- Gordon P. B., Seglen P. O. Prelysosomal convergence of autophagic and endocytic pathways. Biochem Biophys Res Commun. 1988 Feb 29;151(1):40–47. doi: 10.1016/0006-291x(88)90556-6. [DOI] [PubMed] [Google Scholar]
- Grafstein B., Forman D. S. Intracellular transport in neurons. Physiol Rev. 1980 Oct;60(4):1167–1283. doi: 10.1152/physrev.1980.60.4.1167. [DOI] [PubMed] [Google Scholar]
- Hama K., Saito K. Fine structure of the afferent synapse of the hair cells in the saccular macula of the goldfish, with special reference to the anastomosing tubules. J Neurocytol. 1977 Aug;6(4):361–373. doi: 10.1007/BF01178223. [DOI] [PubMed] [Google Scholar]
- Hendil K. B. Autophagy of metabolically inert substances injected into fibroblasts in culture. Exp Cell Res. 1981 Sep;135(1):157–166. doi: 10.1016/0014-4827(81)90308-6. [DOI] [PubMed] [Google Scholar]
- Hendry I. A., Stöckel K., Thoenen H., Iversen L. L. The retrograde axonal transport of nerve growth factor. Brain Res. 1974 Mar 15;68(1):103–121. doi: 10.1016/0006-8993(74)90536-8. [DOI] [PubMed] [Google Scholar]
- Hershko A. The ubiquitin pathway for protein degradation. Trends Biochem Sci. 1991 Jul;16(7):265–268. doi: 10.1016/0968-0004(91)90101-z. [DOI] [PubMed] [Google Scholar]
- Heuser J. E., Reese T. S. Evidence for recycling of synaptic vesicle membrane during transmitter release at the frog neuromuscular junction. J Cell Biol. 1973 May;57(2):315–344. doi: 10.1083/jcb.57.2.315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hollenbeck P. J., Bray D. Rapidly transported organelles containing membrane and cytoskeletal components: their relation to axonal growth. J Cell Biol. 1987 Dec;105(6 Pt 1):2827–2835. doi: 10.1083/jcb.105.6.2827. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Holtzman E. Cytochemical studies of protein transport in the nervous system. Philos Trans R Soc Lond B Biol Sci. 1971 Jun 17;261(839):407–421. doi: 10.1098/rstb.1971.0075. [DOI] [PubMed] [Google Scholar]
- Høyvik H., Gordon P. B., Berg T. O., Strømhaug P. E., Seglen P. O. Inhibition of autophagic-lysosomal delivery and autophagic lactolysis by asparagine. J Cell Biol. 1991 Jun;113(6):1305–1312. doi: 10.1083/jcb.113.6.1305. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kano K., Fendler J. H. Pyranine as a sensitive pH probe for liposome interiors and surfaces. pH gradients across phospholipid vesicles. Biochim Biophys Acta. 1978 May 18;509(2):289–299. doi: 10.1016/0005-2736(78)90048-2. [DOI] [PubMed] [Google Scholar]
- Kopitz J., Kisen G. O., Gordon P. B., Bohley P., Seglen P. O. Nonselective autophagy of cytosolic enzymes by isolated rat hepatocytes. J Cell Biol. 1990 Sep;111(3):941–953. doi: 10.1083/jcb.111.3.941. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kovács A. L., Grinde B., Seglen P. O. Inhibition of autophagic vacuole formation and protein degradation by amino acids in isolated hepatocytes. Exp Cell Res. 1981 Jun;133(2):431–436. doi: 10.1016/0014-4827(81)90336-0. [DOI] [PubMed] [Google Scholar]
- Kovács A. L., Reith A., Seglen P. O. Accumulation of autophagosomes after inhibition of hepatocytic protein degradation by vinblastine, leupeptin or a lysosomotropic amine. Exp Cell Res. 1982 Jan;137(1):191–201. doi: 10.1016/0014-4827(82)90020-9. [DOI] [PubMed] [Google Scholar]
- Kristensson K. Retrograde transport of macromolecules in axons. Annu Rev Pharmacol Toxicol. 1978;18:97–110. doi: 10.1146/annurev.pa.18.040178.000525. [DOI] [PubMed] [Google Scholar]
- Lander A. D., Fujii D. K., Gospodarowicz D., Reichardt L. F. Characterization of a factor that promotes neurite outgrowth: evidence linking activity to a heparan sulfate proteoglycan. J Cell Biol. 1982 Sep;94(3):574–585. doi: 10.1083/jcb.94.3.574. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lee H. C. The voltage-sensitive Na+/H+ exchange in sea urchin spermatozoa flagellar membrane vesicles studied with an entrapped pH probe. J Biol Chem. 1985 Sep 5;260(19):10794–10799. [PubMed] [Google Scholar]
- Liscum L., Hauptman P. J., Hood D. C., Holtzman E. Effect of barium and tetraethylammonium on membrane circulation in frog retinal photoreceptors. J Cell Biol. 1982 Oct;95(1):296–309. doi: 10.1083/jcb.95.1.296. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Margiotta J. F., Berg D. K., Dionne V. E. Cyclic AMP regulates the proportion of functional acetylcholine receptors on chicken ciliary ganglion neurons. Proc Natl Acad Sci U S A. 1987 Nov;84(22):8155–8159. doi: 10.1073/pnas.84.22.8155. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martinez R., Gillies R. J., Giuliano K. A. Effect of serum on the intracellular pH of BALB/c-3T3 cells: serum deprivation causes changes in sensitivity of cells to serum. J Cell Physiol. 1988 Jul;136(1):154–160. doi: 10.1002/jcp.1041360120. [DOI] [PubMed] [Google Scholar]
- Mortimore G. E., Ward W. F. Internalization of cytoplasmic protein by hepatic lysosomes in basal and deprivation-induced proteolytic states. J Biol Chem. 1981 Jul 25;256(14):7659–7665. [PubMed] [Google Scholar]
- Parton R. G., Simons K., Dotti C. G. Axonal and dendritic endocytic pathways in cultured neurons. J Cell Biol. 1992 Oct;119(1):123–137. doi: 10.1083/jcb.119.1.123. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Paschal B. M., Vallee R. B. Retrograde transport by the microtubule-associated protein MAP 1C. Nature. 1987 Nov 12;330(6144):181–183. doi: 10.1038/330181a0. [DOI] [PubMed] [Google Scholar]
- Plomp P. J., Gordon P. B., Meijer A. J., Høyvik H., Seglen P. O. Energy dependence of different steps in the autophagic-lysosomal pathway. J Biol Chem. 1989 Apr 25;264(12):6699–6704. [PubMed] [Google Scholar]
- Pontremoli S., Melloni E. Extralysosomal protein degradation. Annu Rev Biochem. 1986;55:455–481. doi: 10.1146/annurev.bi.55.070186.002323. [DOI] [PubMed] [Google Scholar]
- Punnonen E. L., Reunanen H. Effects of vinblastine, leucine, and histidine, and 3-methyladenine on autophagy in Ehrlich ascites cells. Exp Mol Pathol. 1990 Feb;52(1):87–97. doi: 10.1016/0014-4800(90)90061-h. [DOI] [PubMed] [Google Scholar]
- Reunanen H., Marttinen M., Hirsimäki P. Effects of griseofulvin and nocodazole on the accumulation of autophagic vacuoles in Ehrlich ascites tumor cells. Exp Mol Pathol. 1988 Feb;48(1):97–102. doi: 10.1016/0014-4800(88)90048-2. [DOI] [PubMed] [Google Scholar]
- Russell L. D., Saxena N. K., Turner T. T. Cytoskeletal involvement in spermiation and sperm transport. Tissue Cell. 1989;21(3):361–379. doi: 10.1016/0040-8166(89)90051-7. [DOI] [PubMed] [Google Scholar]
- Schaeffer S. F., Raviola E. Membrane recycling in the cone cell endings of the turtle retina. J Cell Biol. 1978 Dec;79(3):802–825. doi: 10.1083/jcb.79.3.802. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schnapp B. J., Reese T. S. Dynein is the motor for retrograde axonal transport of organelles. Proc Natl Acad Sci U S A. 1989 Mar;86(5):1548–1552. doi: 10.1073/pnas.86.5.1548. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schnapp B. J., Vale R. D., Sheetz M. P., Reese T. S. Single microtubules from squid axoplasm support bidirectional movement of organelles. Cell. 1985 Feb;40(2):455–462. doi: 10.1016/0092-8674(85)90160-6. [DOI] [PubMed] [Google Scholar]
- Schwartz J. H. Axonal transport: components, mechanisms, and specificity. Annu Rev Neurosci. 1979;2:467–504. doi: 10.1146/annurev.ne.02.030179.002343. [DOI] [PubMed] [Google Scholar]
- Schworer C. M., Shiffer K. A., Mortimore G. E. Quantitative relationship between autophagy and proteolysis during graded amino acid deprivation in perfused rat liver. J Biol Chem. 1981 Jul 25;256(14):7652–7658. [PubMed] [Google Scholar]
- Seamon K. B., Padgett W., Daly J. W. Forskolin: unique diterpene activator of adenylate cyclase in membranes and in intact cells. Proc Natl Acad Sci U S A. 1981 Jun;78(6):3363–3367. doi: 10.1073/pnas.78.6.3363. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Seglen P. O., Gordon P. B. Amino acid control of autophagic sequestration and protein degradation in isolated rat hepatocytes. J Cell Biol. 1984 Aug;99(2):435–444. doi: 10.1083/jcb.99.2.435. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Seglen P. O., Gordon P. B., Holen I. Non-selective autophagy. Semin Cell Biol. 1990 Dec;1(6):441–448. [PubMed] [Google Scholar]
- Smith R. S. The short term accumulation of axonally transported organelles in the region of localized lesions of single myelinated axons. J Neurocytol. 1980 Feb;9(1):39–65. doi: 10.1007/BF01205226. [DOI] [PubMed] [Google Scholar]
- Stacey D. W., Allfrey V. G. Evidence for the autophagy of microinjected proteins in HeLA cells. J Cell Biol. 1977 Dec;75(3):807–817. doi: 10.1083/jcb.75.3.807. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Steinberg T. H., Swanson J. A., Silverstein S. C. A prelysosomal compartment sequesters membrane-impermeant fluorescent dyes from the cytoplasmic matrix of J774 macrophages. J Cell Biol. 1988 Sep;107(3):887–896. doi: 10.1083/jcb.107.3.887. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Toyoshima I., Yu H., Steuer E. R., Sheetz M. P. Kinectin, a major kinesin-binding protein on ER. J Cell Biol. 1992 Sep;118(5):1121–1131. doi: 10.1083/jcb.118.5.1121. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tsukita S., Ishikawa H. The movement of membranous organelles in axons. Electron microscopic identification of anterogradely and retrogradely transported organelles. J Cell Biol. 1980 Mar;84(3):513–530. doi: 10.1083/jcb.84.3.513. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vale R. D., Reese T. S., Sheetz M. P. Identification of a novel force-generating protein, kinesin, involved in microtubule-based motility. Cell. 1985 Aug;42(1):39–50. doi: 10.1016/s0092-8674(85)80099-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Vale R. D., Schnapp B. J., Mitchison T., Steuer E., Reese T. S., Sheetz M. P. Different axoplasmic proteins generate movement in opposite directions along microtubules in vitro. Cell. 1985 Dec;43(3 Pt 2):623–632. doi: 10.1016/0092-8674(85)90234-x. [DOI] [PubMed] [Google Scholar]
- Vallee R. B., Shpetner H. S. Motor proteins of cytoplasmic microtubules. Annu Rev Biochem. 1990;59:909–932. doi: 10.1146/annurev.bi.59.070190.004401. [DOI] [PubMed] [Google Scholar]
- Weiss D. G., Langford G. M., Seitz-Tutter D., Keller F. Dynamic instability and motile events of native microtubules from squid axoplasm. Cell Motil Cytoskeleton. 1988;10(1-2):285–295. doi: 10.1002/cm.970100133. [DOI] [PubMed] [Google Scholar]