Ubiquitin Specific Peptidase 19 (USP19)

USP19 is widely expressed in various tissues including skeletal muscle. Expression of USP19 mRNA increased in skeletal muscle by ~30-200% in rat skeletal muscle atrophying in response to fasting, streptozotocin induced diabetes, dexamethasone treatment and cancer. Increased mRNA levels during fasting returned to normal with refeeding, but one day later than the normalization of rates of proteolysis and coincided instead with recovery of muscle mass. Indeed, in all catabolic treatments USP19 mRNA was inversely correlated with muscle mass and provided an index of muscle mass that may be useful in many pathological conditions, using small human muscle biopsies. USP19 may also be involved in posttranslational processing of polyubiquitin produced de novo in response to induction of the polyubiquitin genes seen under these conditions.