 "In-vitro", tau proteins have been shown to directly bind microtubules, promote nucleation and prevent disassembly, and to induce the formation of parallel arrays.Additionally, tau proteins have also been shown to stabilize microtubules in axons and have been implicated in Alzheimer's disease.The second class is composed of MAPs with a molecular weight of 200-1000 kDa, of which there are four known types