title: Physiopathology and regulation of factor XIII.
abstract: Factor XIII is a plasma transglutaminase. Transglutaminases are at least 8 enzymes which cross-link a number of proteins. This type of reaction not only enhances the original functions of substrate proteins, but also adds new functions to them. Factor XIII in plasma is a tetramer (A2B2), and the A subunit contains the active site. Although transglutaminases are homologous, the nucleotide sequences in their 5'-flanking region differ significantly. Accordingly, transcription factors play a major role in the cell type-specific expression of each transglutaminase. A variety of missense and nonsense mutations, and deletions/insertions with or without out-of-frame shift/premature termination and splicing abnormalities have been identified in the genes for A and B subunits in factor XIII deficiency. In some cases, the mRNA level of the A or B subunit was severely reduced. Molecular and cellular bases have also been explored by expression experiments and by molecular modeling. In most cases, impaired folding and/or conformational change of the mutant A or B subunit leads to both intra- and extra-cellular instability, which is responsible for factor XIII deficiency.
authors.affiliation: Department of Molecular Patho-Biochemistry and Patho-Biology, Yamagata University School of Medicine, Japan. aichinos@med.id.yamagata-u.ac.jp
authors.forename: A
authors.initials: A
authors.lastname: Ichinose
mesh_terms: D005176:Factor XIII / Q000737:chemistry / Q000235:genetics*; D005177:Factor XIII Deficiency / Q000209:etiology / Q000235:genetics*; D005786:Gene Expression Regulation; D006801:Humans; D009154:Mutation; D017434:Protein Structure, Tertiary; D011503:Transglutaminases / Q000737:chemistry / Q000235:genetics
chemical_list: D005176:Factor XIII; D011503:Transglutaminases