User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2009/05/08/Kinetic analysis of GTP hydrolysis associated with tubulin polymerization review
These are my thoughts on this paper. Read the paper before you read my comments please.
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.