Carboxypeptidase A4 (CPA4), a novel upstream regulator of mTOR, is significantly upregulated in isoprenaline (ISO)-induced cardiac hypertrophy in mice, promoting hypertrophy by enhancing PI3K-AKT signaling and activating mTOR and downstream S6K1 phosphorylation. The gene discussed is MTOR; the disease is cardiac hypertrophy.