User:Andy Maloney/Kinesin & Microtubule Page/Microtubule papers/Tubulin assembly in the presence of calcium ions and taxol microtubule bundling and formation of macrotubule-ring complexes

Disclaimer

These are my notes. Please read the article before reading my notes.

Paper

Tubulin assembly in the presence of calcium ions and taxol: microtubule bundling and formation of macrotubule-ring complexes.

Notes

• This paper describes how calcium influences different assemblies of microtubules when they are polymerized in the presence of calcium.
• They state that protofilaments are about 5 nm in width.
• Ohhh, reference to glycerol changing the hydrate shell of proteins!
• Tubulin from porcine brains.
• Polymerization of tubulin was done in:
  • 2.5 mg/mL tubulin
  • 20 mM Morpholinethane sulfonic acid
  • 80 mM NaCl
  • 1 mM EGTA
  • 0.5 mM MgCl₂
  • 0.36 mM GTP
  • 10 µM Taxol
  • pH 6.4
  • Calcium was added either before polymerization or after.
• They did not see odd microtubule structures in the presence of calcium without Taxol.
  • When incubated at 0˚C with Taxol and then polymerized with 2-30 mM calcium, bundles occurred. This is reminiscent of funky structures that can arise from Taxol discussed in this paper.
  • When incubated with calcium and then polymerized in Taxol, they saw "macrotubules". These macrotubules were sometimes not fully structured, i.e. they had holes or gaps in them.
• There is an awesome picture of a coiled protofilament.
• Calcium prevents both lateral microtubule assembly and longitudinal tubulin-tubulin dimer assembly.