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. 1998 Jul 1;17(13):3597–3607. doi: 10.1093/emboj/17.13.3597

Aut2p and Aut7p, two novel microtubule-associated proteins are essential for delivery of autophagic vesicles to the vacuole.

T Lang 1, E Schaeffeler 1, D Bernreuther 1, M Bredschneider 1, D H Wolf 1, M Thumm 1
PMCID: PMC1170696  PMID: 9649430

Abstract

AUT2 and AUT7, two novel genes essential for autophagocytosis in the yeast Saccharomyces cerevisiae were isolated. AUT7 was identified as a low copy suppressor of autophagic defects in aut2-1 cells. Aut7p is a homologue of the rat microtubule-associated protein (MAP) light chain 3 (LC3). Aut2p and Aut7p interact physically. Aut7p is attached to microtubules via Aut2p, which interacts with tubulins Tub1p and Tub2p. aut2- and aut7-deleted cells are unable to deliver autophagic vesicles and the precursor of aminopeptidase I to the vacuole. Double membrane-layered autophagosome-like vesicles accumulate in the cytoplasm of these cells. Our findings suggest that microtubules and an attached protein complex of Aut2p and Aut7p are involved in the delivery of autophagic vesicles to the vacuole.

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Selected References

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  1. Aplin A., Jasionowski T., Tuttle D. L., Lenk S. E., Dunn W. A., Jr Cytoskeletal elements are required for the formation and maturation of autophagic vacuoles. J Cell Physiol. 1992 Sep;152(3):458–466. doi: 10.1002/jcp.1041520304. [DOI] [PubMed] [Google Scholar]
  2. Baba M., Takeshige K., Baba N., Ohsumi Y. Ultrastructural analysis of the autophagic process in yeast: detection of autophagosomes and their characterization. J Cell Biol. 1994 Mar;124(6):903–913. doi: 10.1083/jcb.124.6.903. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Barnes G., Louie K. A., Botstein D. Yeast proteins associated with microtubules in vitro and in vivo. Mol Biol Cell. 1992 Jan;3(1):29–47. doi: 10.1091/mbc.3.1.29. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Codogno P., Ogier-Denis E., Houri J. J. Signal transduction pathways in macroautophagy. Cell Signal. 1997 Feb;9(2):125–130. doi: 10.1016/s0898-6568(96)00130-1. [DOI] [PubMed] [Google Scholar]
  5. Cubitt A. B., Heim R., Adams S. R., Boyd A. E., Gross L. A., Tsien R. Y. Understanding, improving and using green fluorescent proteins. Trends Biochem Sci. 1995 Nov;20(11):448–455. doi: 10.1016/s0968-0004(00)89099-4. [DOI] [PubMed] [Google Scholar]
  6. Dunn W. A., Jr Autophagy and related mechanisms of lysosome-mediated protein degradation. Trends Cell Biol. 1994 Apr;4(4):139–143. doi: 10.1016/0962-8924(94)90069-8. [DOI] [PubMed] [Google Scholar]
  7. 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]
  8. Egner R., Thumm M., Straub M., Simeon A., Schüller H. J., Wolf D. H. Tracing intracellular proteolytic pathways. Proteolysis of fatty acid synthase and other cytoplasmic proteins in the yeast Saccharomyces cerevisiae. J Biol Chem. 1993 Dec 25;268(36):27269–27276. [PubMed] [Google Scholar]
  9. Fields S., Song O. A novel genetic system to detect protein-protein interactions. Nature. 1989 Jul 20;340(6230):245–246. doi: 10.1038/340245a0. [DOI] [PubMed] [Google Scholar]
  10. Fields S., Sternglanz R. The two-hybrid system: an assay for protein-protein interactions. Trends Genet. 1994 Aug;10(8):286–292. doi: 10.1016/0168-9525(90)90012-u. [DOI] [PubMed] [Google Scholar]
  11. Güldener U., Heck S., Fielder T., Beinhauer J., Hegemann J. H. A new efficient gene disruption cassette for repeated use in budding yeast. Nucleic Acids Res. 1996 Jul 1;24(13):2519–2524. doi: 10.1093/nar/24.13.2519. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Harding T. M., Hefner-Gravink A., Thumm M., Klionsky D. J. Genetic and phenotypic overlap between autophagy and the cytoplasm to vacuole protein targeting pathway. J Biol Chem. 1996 Jul 26;271(30):17621–17624. doi: 10.1074/jbc.271.30.17621. [DOI] [PubMed] [Google Scholar]
  13. Harding T. M., Morano K. A., Scott S. V., Klionsky D. J. Isolation and characterization of yeast mutants in the cytoplasm to vacuole protein targeting pathway. J Cell Biol. 1995 Nov;131(3):591–602. doi: 10.1083/jcb.131.3.591. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Interthal H., Bellocq C., Bähler J., Bashkirov V. I., Edelstein S., Heyer W. D. A role of Sep1 (= Kem1, Xrn1) as a microtubule-associated protein in Saccharomyces cerevisiae. EMBO J. 1995 Mar 15;14(6):1057–1066. doi: 10.1002/j.1460-2075.1995.tb07088.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. James P., Halladay J., Craig E. A. Genomic libraries and a host strain designed for highly efficient two-hybrid selection in yeast. Genetics. 1996 Dec;144(4):1425–1436. doi: 10.1093/genetics/144.4.1425. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Klionsky D. J., Cueva R., Yaver D. S. Aminopeptidase I of Saccharomyces cerevisiae is localized to the vacuole independent of the secretory pathway. J Cell Biol. 1992 Oct;119(2):287–299. doi: 10.1083/jcb.119.2.287. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kuznetsov S. A., Gelfand V. I. 18 kDa microtubule-associated protein: identification as a new light chain (LC-3) of microtubule-associated protein 1 (MAP-1). FEBS Lett. 1987 Feb 9;212(1):145–148. doi: 10.1016/0014-5793(87)81574-0. [DOI] [PubMed] [Google Scholar]
  18. Lawrence B. P., Brown W. J. Autophagic vacuoles rapidly fuse with pre-existing lysosomes in cultured hepatocytes. J Cell Sci. 1992 Jul;102(Pt 3):515–526. doi: 10.1242/jcs.102.3.515. [DOI] [PubMed] [Google Scholar]
  19. Mann S. S., Hammarback J. A. Gene localization and developmental expression of light chain 3: a common subunit of microtubule-associated protein 1A(MAP1A) and MAP1B. J Neurosci Res. 1996 Mar 1;43(5):535–544. doi: 10.1002/(SICI)1097-4547(19960301)43:5<535::AID-JNR3>3.0.CO;2-J. [DOI] [PubMed] [Google Scholar]
  20. Mann S. S., Hammarback J. A. Molecular characterization of light chain 3. A microtubule binding subunit of MAP1A and MAP1B. J Biol Chem. 1994 Apr 15;269(15):11492–11497. [PubMed] [Google Scholar]
  21. Montoliu L., Rigau J., Puigdomènech P. A tandem of alpha-tubulin genes preferentially expressed in radicular tissues from Zea mays. Plant Mol Biol. 1990 Jan;14(1):1–15. doi: 10.1007/BF00015650. [DOI] [PubMed] [Google Scholar]
  22. Mortimore G. E., Miotto G., Venerando R., Kadowaki M. Autophagy. Subcell Biochem. 1996;27:93–135. doi: 10.1007/978-1-4615-5833-0_4. [DOI] [PubMed] [Google Scholar]
  23. Pedrotti B., Francolini M., Cotelli F., Islam K. Modulation of microtubule shape in vitro by high molecular weight microtubule associated proteins MAP1A, MAP1B, and MAP2. FEBS Lett. 1996 Apr 15;384(2):147–150. doi: 10.1016/0014-5793(96)00308-0. [DOI] [PubMed] [Google Scholar]
  24. Rose M. D., Novick P., Thomas J. H., Botstein D., Fink G. R. A Saccharomyces cerevisiae genomic plasmid bank based on a centromere-containing shuttle vector. Gene. 1987;60(2-3):237–243. doi: 10.1016/0378-1119(87)90232-0. [DOI] [PubMed] [Google Scholar]
  25. Sato-Yoshitake R., Shiomura Y., Miyasaka H., Hirokawa N. Microtubule-associated protein 1B: molecular structure, localization, and phosphorylation-dependent expression in developing neurons. Neuron. 1989 Aug;3(2):229–238. doi: 10.1016/0896-6273(89)90036-6. [DOI] [PubMed] [Google Scholar]
  26. Schatz P. J., Solomon F., Botstein D. Isolation and characterization of conditional-lethal mutations in the TUB1 alpha-tubulin gene of the yeast Saccharomyces cerevisiae. Genetics. 1988 Nov;120(3):681–695. doi: 10.1093/genetics/120.3.681. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Schlumpberger M., Schaeffeler E., Straub M., Bredschneider M., Wolf D. H., Thumm M. AUT1, a gene essential for autophagocytosis in the yeast Saccharomyces cerevisiae. J Bacteriol. 1997 Feb;179(4):1068–1076. doi: 10.1128/jb.179.4.1068-1076.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Scott S. V., Hefner-Gravink A., Morano K. A., Noda T., Ohsumi Y., Klionsky D. J. Cytoplasm-to-vacuole targeting and autophagy employ the same machinery to deliver proteins to the yeast vacuole. Proc Natl Acad Sci U S A. 1996 Oct 29;93(22):12304–12308. doi: 10.1073/pnas.93.22.12304. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Seglen P. O., Berg T. O., Blankson H., Fengsrud M., Holen I., Strømhaug P. E. Structural aspects of autophagy. Adv Exp Med Biol. 1996;389:103–111. doi: 10.1007/978-1-4613-0335-0_12. [DOI] [PubMed] [Google Scholar]
  30. Shiomura Y., Hirokawa N. The molecular structure of microtubule-associated protein 1A (MAP1A) in vivo and in vitro. An immunoelectron microscopy and quick-freeze, deep-etch study. J Neurosci. 1987 May;7(5):1461–1469. doi: 10.1523/JNEUROSCI.07-05-01461.1987. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Solomon F. Analyses of the cytoskeleton in Saccharomyces cerevisiae. Annu Rev Cell Biol. 1991;7:633–662. doi: 10.1146/annurev.cb.07.110191.003221. [DOI] [PubMed] [Google Scholar]
  32. Stearns T. Green fluorescent protein. The green revolution. Curr Biol. 1995 Mar 1;5(3):262–264. doi: 10.1016/s0960-9822(95)00056-x. [DOI] [PubMed] [Google Scholar]
  33. Straub M., Bredschneider M., Thumm M. AUT3, a serine/threonine kinase gene, is essential for autophagocytosis in Saccharomyces cerevisiae. J Bacteriol. 1997 Jun;179(12):3875–3883. doi: 10.1128/jb.179.12.3875-3883.1997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Thumm M., Egner R., Koch B., Schlumpberger M., Straub M., Veenhuis M., Wolf D. H. Isolation of autophagocytosis mutants of Saccharomyces cerevisiae. FEBS Lett. 1994 Aug 1;349(2):275–280. doi: 10.1016/0014-5793(94)00672-5. [DOI] [PubMed] [Google Scholar]
  35. Wach A., Brachat A., Pöhlmann R., Philippsen P. New heterologous modules for classical or PCR-based gene disruptions in Saccharomyces cerevisiae. Yeast. 1994 Dec;10(13):1793–1808. doi: 10.1002/yea.320101310. [DOI] [PubMed] [Google Scholar]
  36. Wilson R., Ainscough R., Anderson K., Baynes C., Berks M., Bonfield J., Burton J., Connell M., Copsey T., Cooper J. 2.2 Mb of contiguous nucleotide sequence from chromosome III of C. elegans. Nature. 1994 Mar 3;368(6466):32–38. doi: 10.1038/368032a0. [DOI] [PubMed] [Google Scholar]
  37. Winsor B., Schiebel E. Review: an overview of the Saccharomyces cerevisiae microtubule and microfilament cytoskeleton. Yeast. 1997 Apr;13(5):399–434. doi: 10.1002/(SICI)1097-0061(199704)13:5<399::AID-YEA126>3.0.CO;2-9. [DOI] [PubMed] [Google Scholar]

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