HAP1 and Huntington disease: HAP1 interacts with the kinesin family motor protein 5 (KIF5), and this interaction-mediated anterograde transport of GABAARs and GluR2-containing AMPARs along microtubules in dendrites is disrupted by mHTT, leading to disrupted excitatory/inhibitory balance in HD (Twelvetrees et al., 2010; Mandal et al., 2011; Yuen et al., 2012).