Figure 2.

Model of microtubule protofilament with bound kinesin and tau. The protofilament consists of alternating subunits of α‐ and β‐tubulin (∼450 residues each) arranged in a polar fashion. The head domain of kinesin, a microtubule‐dependent motor protein (∼350 residues), has the compact folding typical of most cytoplasmic proteins. By contrast, tau is natively unfolded, its structure is unknown in detail and modeled here as a random chain. Note that tau occupies a much larger volume than kinesin or tubulin.