Troponin I, fast skeletal muscle, also known as TNNI2, is a member of the troponin I gene family, and a component of the troponin complex including troponin T, troponin C and troponin I subunits. The troponin complex, along with tropomyosin, is responsible for the calcium-dependent regulation of striated muscle contraction. This protein also suppresses tumor growth in human ovarian carcinoma. Mutations in TNNI2 cause myopathy and distal arthrogryposis type 2B. Recombinant human TNNI2 protein, fused to His-tag at N-terminus, was expressed in E.coli.