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. 1995 Dec;7(12):2129–2138. doi: 10.1105/tpc.7.12.2129

End-to-end annealing of plant microtubules by the p86 subunit of eukaryotic initiation factor-(iso)4F.

J D Hugdahl 1, C L Bokros 1, L C Morejohn 1
PMCID: PMC161067  PMID: 8718623

Abstract

The p86 subunit of eukaryotic initiation factor-(iso)4F from wheat germ exhibits saturable and substoichiometric binding to maize microtubules, induces microtubule bundling in vitro, and is colocalized or closely associated with cortical microtubule bundles in maize root cells, indicating its function as a microtubule-associated protein (MAP). The effects of p86 on the growth of short, taxol-stabilized maize microtubules were investigated. Pure microtubules underwent a gradual length redistribution, an increase in mean length, and a decrease in number concentration consistent with an end-to-end annealing mechanism of microtubule growth. Saturating p86 enhanced the microtubule length distribution and produced significantly longer and fewer microtubules than the control, indicating a facilitation of annealing by p86. Confirmation of endwise annealing rather than of dynamic instability as the mechanism for microtubule growth was made using mammalian MAP2, which also promoted the redistribution of length, increase in mean length, and decrease in number concentration of taxol-stabilized maize microtubules. Enhancement of microtubule growth occurred concomitant with bundling by p86, indicating that an alignment of microtubules in bundles facilitated endwise annealing kinetics. The results demonstrate that nonfacile plant microtubules can spontaneously elongate by endwise annealing and that MAPs enhance the rate of annealing. The p86 subunit of eukaryotic initiation factor-(iso)4F may be an important regulator of microtubule dynamics in plant cells.

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Selected References

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  1. Allen M. L., Metz A. M., Timmer R. T., Rhoads R. E., Browning K. S. Isolation and sequence of the cDNAs encoding the subunits of the isozyme form of wheat protein synthesis initiation factor 4F. J Biol Chem. 1992 Nov 15;267(32):23232–23236. [PubMed] [Google Scholar]
  2. Bokros C. L., Hugdahl J. D., Hanesworth V. R., Murthy J. V., Morejohn L. C. Characterization of the reversible taxol-induced polymerization of plant tubulin into microtubules. Biochemistry. 1993 Apr 6;32(13):3437–3447. doi: 10.1021/bi00064a030. [DOI] [PubMed] [Google Scholar]
  3. Bokros C. L., Hugdahl J. D., Kim H. H., Hanesworth V. R., van Heerden A., Browning K. S., Morejohn L. C. Function of the p86 subunit of eukaryotic initiation factor (iso)4F as a microtubule-associated protein in plant cells. Proc Natl Acad Sci U S A. 1995 Jul 18;92(15):7120–7124. doi: 10.1073/pnas.92.15.7120. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1006/abio.1976.9999. [DOI] [PubMed] [Google Scholar]
  5. Brandt R., Lee G. Orientation, assembly, and stability of microtubule bundles induced by a fragment of tau protein. Cell Motil Cytoskeleton. 1994;28(2):143–154. doi: 10.1002/cm.970280206. [DOI] [PubMed] [Google Scholar]
  6. Browning K. S., Webster C., Roberts J. K., Ravel J. M. Identification of an isozyme form of protein synthesis initiation factor 4F in plants. J Biol Chem. 1992 May 15;267(14):10096–10100. [PubMed] [Google Scholar]
  7. Cassimeris L., Pryer N. K., Salmon E. D. Real-time observations of microtubule dynamic instability in living cells. J Cell Biol. 1988 Dec;107(6 Pt 1):2223–2231. doi: 10.1083/jcb.107.6.2223. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Condeelis J. Elongation factor 1 alpha, translation and the cytoskeleton. Trends Biochem Sci. 1995 May;20(5):169–170. doi: 10.1016/s0968-0004(00)88998-7. [DOI] [PubMed] [Google Scholar]
  9. Davis A., Sage C. R., Dougherty C. A., Farrell K. W. Microtubule dynamics modulated by guanosine triphosphate hydrolysis activity of beta-tubulin. Science. 1994 May 6;264(5160):839–842. doi: 10.1126/science.8171338. [DOI] [PubMed] [Google Scholar]
  10. Drechsel D. N., Hyman A. A., Cobb M. H., Kirschner M. W. Modulation of the dynamic instability of tubulin assembly by the microtubule-associated protein tau. Mol Biol Cell. 1992 Oct;3(10):1141–1154. doi: 10.1091/mbc.3.10.1141. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Gelfand V. I., Bershadsky A. D. Microtubule dynamics: mechanism, regulation, and function. Annu Rev Cell Biol. 1991;7:93–116. doi: 10.1146/annurev.cb.07.110191.000521. [DOI] [PubMed] [Google Scholar]
  12. Hotani H., Horio T. Dynamics of microtubules visualized by darkfield microscopy: treadmilling and dynamic instability. Cell Motil Cytoskeleton. 1988;10(1-2):229–236. doi: 10.1002/cm.970100127. [DOI] [PubMed] [Google Scholar]
  13. Hugdahl J. D., Bokros C. L., Hanesworth V. R., Aalund G. R., Morejohn L. C. Unique functional characteristics of the polymerization and MAP binding regulatory domains of plant tubulin. Plant Cell. 1993 Sep;5(9):1063–1080. doi: 10.1105/tpc.5.9.1063. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hugdahl J. D., Morejohn L. C. Deficient nucleation during co-polymerization of mammalian MAP2 and tobacco tubulin. Biochem Mol Biol Int. 1994 Sep;34(2):375–384. [PubMed] [Google Scholar]
  15. Kowalski R. J., Williams R. C., Jr Microtubule-associated protein 2 alters the dynamic properties of microtubule assembly and disassembly. J Biol Chem. 1993 May 5;268(13):9847–9855. [PubMed] [Google Scholar]
  16. Kumar N. Taxol-induced polymerization of purified tubulin. Mechanism of action. J Biol Chem. 1981 Oct 25;256(20):10435–10441. [PubMed] [Google Scholar]
  17. Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
  18. Margolis R. L., Wilson L. Opposite end assembly and disassembly of microtubules at steady state in vitro. Cell. 1978 Jan;13(1):1–8. doi: 10.1016/0092-8674(78)90132-0. [DOI] [PubMed] [Google Scholar]
  19. Mitchison T., Kirschner M. Dynamic instability of microtubule growth. Nature. 1984 Nov 15;312(5991):237–242. doi: 10.1038/312237a0. [DOI] [PubMed] [Google Scholar]
  20. Morejohn L. C., Fosket D. E. Higher plant tubulin identified by self-assembly into microtubules in vitro. Nature. 1982 Jun 3;297(5865):426–428. doi: 10.1038/297426a0. [DOI] [PubMed] [Google Scholar]
  21. Qaw F., Calverley M. J., Schroeder N. J., Trafford D. J., Makin H. L., Jones G. In vivo metabolism of the vitamin D analog, dihydrotachysterol. Evidence for formation of 1 alpha,25- and 1 beta,25-dihydroxy-dihydrotachysterol metabolites and studies of their biological activity. J Biol Chem. 1993 Jan 5;268(1):282–292. [PubMed] [Google Scholar]
  22. Rothwell S. W., Grasser W. A., Baker H. N., Murphy D. B. The relative contributions of polymer annealing and subunit exchange to microtubule dynamics in vitro. J Cell Biol. 1987 Aug;105(2):863–874. doi: 10.1083/jcb.105.2.863. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Rothwell S. W., Grasser W. A., Murphy D. B. End-to-end annealing of microtubules in vitro. J Cell Biol. 1986 Feb;102(2):619–627. doi: 10.1083/jcb.102.2.619. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Schulze E., Kirschner M. Microtubule dynamics in interphase cells. J Cell Biol. 1986 Mar;102(3):1020–1031. doi: 10.1083/jcb.102.3.1020. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Shiina N., Gotoh Y., Nishida E. A novel homo-oligomeric protein responsible for an MPF-dependent microtubule-severing activity. EMBO J. 1992 Dec;11(13):4723–4731. doi: 10.1002/j.1460-2075.1992.tb05577.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. St Johnston D. The intracellular localization of messenger RNAs. Cell. 1995 Apr 21;81(2):161–170. doi: 10.1016/0092-8674(95)90324-0. [DOI] [PubMed] [Google Scholar]
  27. Vale R. D. Severing of stable microtubules by a mitotically activated protein in Xenopus egg extracts. Cell. 1991 Feb 22;64(4):827–839. doi: 10.1016/0092-8674(91)90511-v. [DOI] [PubMed] [Google Scholar]
  28. Williams R. C., Jr, Rone L. A. End-to-end joining of taxol-stabilized GDP-containing microtubules. J Biol Chem. 1989 Jan 25;264(3):1663–1670. [PubMed] [Google Scholar]
  29. Wilson L., Miller H. P., Farrell K. W., Snyder K. B., Thompson W. C., Purich D. L. Taxol stabilization of microtubules in vitro: dynamics of tubulin addition and loss at opposite microtubule ends. Biochemistry. 1985 Sep 10;24(19):5254–5262. doi: 10.1021/bi00340a045. [DOI] [PubMed] [Google Scholar]
  30. Yamauchi P. S., Flynn G. C., Marsh R. L., Purich D. L. Reduction in microtubule dynamics in vitro by brain microtubule-associated proteins and by a microtubule-associated protein-2 second repeated sequence analogue. J Neurochem. 1993 Mar;60(3):817–826. doi: 10.1111/j.1471-4159.1993.tb03225.x. [DOI] [PubMed] [Google Scholar]
  31. Yuan M., Shaw P. J., Warn R. M., Lloyd C. W. Dynamic reorientation of cortical microtubules, from transverse to longitudinal, in living plant cells. Proc Natl Acad Sci U S A. 1994 Jun 21;91(13):6050–6053. doi: 10.1073/pnas.91.13.6050. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. van Heerden A., Browning K. S. Expression in Escherichia coli of the two subunits of the isozyme form of wheat germ protein synthesis initiation factor 4F. Purification of the subunits and formation of an enzymatically active complex. J Biol Chem. 1994 Jul 1;269(26):17454–17457. [PubMed] [Google Scholar]

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