HTT and Huntington disease: Additionally, the interaction between PSD-95 and stargazin (TARP γ-2), a key component of diffusional trapping machinery [20, 44], is dramatically disrupted in the hippocampus of HdhQ111/Q111 knock-in HD mouse models and in hippocampal neurons overexpressing full-length huntingtin, despite the unchanged protein levels of stargazin and PSD-95 [64].