MAP2-mediated binding of chromaffin granules to microtubules

F. F. Severin*, N. A. Shanina, S. A. Kuznetsov, V. I. Gelfand

*Corresponding author for this work

Research output: Contribution to journalArticle

15 Scopus citations

Abstract

We have examined the interaction of chromaffin granules from bovine adrenal modulla with microtubules. Chromaffin granules were mixed with microtubules made of phosphocellulose-purified tubulin, and pelleted through a 1.6 M sucrose cushion at 12000 × g for 10 min. Both components (granules and microtubules) were pelleted when added together but not separately. This result indicates that granules form a heavy complex with the microtubules. Such a complex was visualized by an electron microscopy of the granule/microtubule mixture. Treatment of the granules with trypsin abolished their ability to interact with the microtubules. The binding of the granules to the microtubules: (i) was not sensitive to ATP: and (ii) was completely inhibited by the cleavage of C-terminal peptides of α- and β-subunits of tubulin with subtilisin. These relationships suggest that the granule binding is mediated by one of the structural microtubule-associated proteins rather than by microtubule-dependent translocators. For identification of protein(s) mediating the binding, the granules were solubilized with Triton X-100, soluble proteins were mixed with the microtubules, and microtubules with bound proteins were pelleted through a glycerol cushion. At least one granule protein interacting with the microtubules was found in the pellet. This protein was identified as MAP2 according to its electrophoretic mobility and reactivity with a MAP2 antibody. Affinity chromatography of solubilized proteins on a column containing taxol-stabilized microtubules also revealed MAP2 as a protein of chromaffin granules interacting with the microtubules.

Original languageEnglish (US)
Pages (from-to)65-68
Number of pages4
JournalFEBS Letters
Volume282
Issue number1
DOIs
StatePublished - Apr 22 1991

Keywords

  • Adrenal medulla
  • Chromaffin granule
  • MAP2
  • Membrane-microtubule interaction
  • Microtubule

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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