title: TNNI1, TNNI2 and TNNI3: Evolution, regulation, and protein structure-function relationships.
abstract: Troponin I (TnI) is the inhibitory subunit of the troponin complex in the sarcomeric thin filament of striated muscle and plays a central role in the calcium regulation of contraction and relaxation. Vertebrate TnI has evolved into three isoforms encoded by three homologous genes: TNNI1 for slow skeletal muscle TnI, TNNI2 for fast skeletal muscle TnI and TNNI3 for cardiac TnI, which are expressed under muscle type-specific and developmental regulations. To summarize the current knowledge on the TnI isoform genes and products, this review focuses on the evolution, gene regulation, posttranslational modifications, and structure-function relationship of TnI isoform proteins. Their physiological and medical significances are also discussed.
authors.affiliation: Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: Juan-Juan
authors.initials: JJ
authors.lastname: Sheng
authors.affiliation: Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA. Electronic address: jjin@med.wayne.edu.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Jin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D005786:Gene Expression Regulation; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000737:chemistry / Q000235:genetics*; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D019210:Troponin I / Q000737:chemistry / Q000235:genetics*
chemical_list: C581522:TNNI1 protein, human; C518658:TNNI2 protein, human; D019210:Troponin I; D017346:Protein Serine-Threonine Kinases; C481078:TNNI3K protein, human; D020930:MAP Kinase Kinase Kinases
keywords: Cardiac and skeletal muscle; Evolution; Gene regulation; Isoform; Posttranslational modification; Troponin I