title: Cytoskeletal scaffolding proteins interact with Lynch-Syndrome associated mismatch repair protein MLH1.
abstract: The involvement of MLH1 in several mismatch repair-independent cellular processes has been reported. In an attempt to gain further insight into the protein's cellular functions, we screened for novel interacting partners of MLH1 utilizing a bacterial two-hybrid system. Numerous unknown interacting proteins were identified, suggesting novel biological roles of MLH1. The network of MLH1 and its partner proteins involves a multitude of cellular processes. Integration of our data with the "General Repository for Interaction Datasets" highlighted that MLH1 exhibits relationships to three interacting pairs of proteins involved in cytoskeletal and filament organization: Thymosin beta 4 and Actin gamma, Cathepsin B and Annexin A2 as well as Spectrin alpha and Desmin. Coimmunoprecipitation and colocalization experiments validated the interaction of MLH1 with these proteins. Differential mRNA levels of many of the identified proteins, detected by microarray analysis comparing MLH1-deficient and -proficient cell lines, support the assumed interplay of MLH1 and the identified candidate proteins. By siRNA knock down of MLH1, we demonstrated the functional impact of MLH1-Actin interaction on filament organization and propose that dysregulation of MLH1 plays an essential role in cytoskeleton dynamics. Our data suggest novel roles of MLH1 in cellular organization and colorectal cancerogenesis.
authors: Medical Clinic I, Biomedical Research Laboratory, Goethe-University, Frankfurt, Germany. a.brieger@em.uni-frankfurt.de
authors: Angela
authors: A
authors: Brieger
authors: Boris
authors: B
authors: Adryan
authors: Fabian
authors: F
authors: Wolpert
authors: Sandra
authors: S
authors: Passmann
authors: Stefan
authors: S
authors: Zeuzem
authors: Jörg
authors: J
authors: Trojan
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D006801:Humans; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D003598:Cytoskeletal Proteins; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D000070957:MutL Protein Homolog 1