As such, we propose that the (de)SUMOylation of PICK1 may also be a requirement for PICK1 binding to mGLUR7, further enhancing or inhibiting the surface expression of mGLUR7, since SUMOylation is often used by the cell as a modification to direct protein subcellular relocalization.96 SUMOylation of PICK1 potentially highlights a mechanism through which SUMO may control the surface presence of receptors like mGLUR7; this pathway may be involved in the aberrant neuronal excitability and firing characteristic of HD pathology and will be studied further in future studies. This evidence concerns the gene GRM7 and Huntington disease.