User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2009/05/08/Kinetic analysis of GTP hydrolysis associated with tubulin polymerization review

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These are my thoughts on this paper. Read the paper before you read my comments please.


Kinetic analysis of GTP hydrolysis associated with tubulin polymerization


So I started out with this question

Question: How does tubulin polymerize into microtubules?

This paper gives me at least a reference for what is already known in the field and that is, tubulin carries GTP on both its α and β subunits. When two tubulin heterodimers combine, the β site hydrolyzes GTP to form GDP. I think the GDP gets stuck but I'm not sure.

  • They note that microtubules can be stabilized with nonhydrolyzable analogues of GTP such as GMPCPP.
  • I got another reference where they actually show GTP hydrolysis occurs at the β subunit, Reference.
  • They also state that free GTP in solution can be exchanged with bound GTP on tubulin that has been polymerized into microtubules.

Take home This was a nice paper that answered the question for me of "where are the references that say GTP is needed". Of course, I still don't understand why polymerization needs magnesium ions.

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