USP14 is a ubiquitin specific protease that associates with the proteasome. This association with the proteasome has been shown to enhance the enzymatic activity of the proteasome. Recent studies have demonstrated that USP14 expression in certain cancers correlates with metastasis. Using a chemical probe researchers have shown that USP14 can interact with ISG15, a ubiquitin-like protein. Additionally, deficiencies in cytosolic proteasomes within the Nervous System have been linked to formation of intracellular protein aggregates, a hallmark of Alzheimer’s Disease. These will, in turn, lead to cell death.