Re: how similar are tau and microtubule-associated protein 2?

Tau and MAP2 are both microtubule associated proteins that are expressed 
primarily in neurons. Within neurons, tau is localized predominately in 
axons, while MAP2 is specifically localized to dendrites. They both 
contain a C-terminal microtubule-binding region characterized by imperfect 
tandem 
repeats. This microtuble-binding region is highly conserved between MAP2 
and tau, with 60-70% sequence similarity. However, the N-terminal regions 
(called "projection domains" as they are thought to project out from the 
surface of the microtubule) differ greatly between the two proteins and 
probably serve different functions in each protein.

The association of both MAP2 and tau with microtubules is regulated in 
part 
by phosphorylation. In general, phosphorylation decreases the affinity of 
the MAPs for microtubules. MAP2 and tau are phosphorylated by many of the 
same kinases, including CDK5, MARK, PKA and GSK3-beta. Therefore, 
substances that activated any of these kinases would be likely to lead to 
hyperphosphorylation of both MAP2 and tau.

* Wiche, G., Oberkanins, C. & Himmler, A. (1991) Molecular structure 
and function of microtubule-associated proteins. Int. Rev. Cytol. 124: 
217-273.
* Cassimeris L, Spittle C. (2001) Regulation of microtubule-associated 
proteins. Int Rev Cytol. 210:163-226.

Dmitri Leonoudakis with help from Janis Bunker