Conversely, N-terminal cleavage of 26 or 27 amino acids from cTnI was observed in chronic simulated microgravity (11), heart failure (12), and even in normal hearts (12) and mimicked Ser-23/24 phosphorylation by reducing myofibrillar Ca2+ sensitivity and accelerating muscle relaxation. The gene discussed is TNNI3; the disease is heart failure.