title: Inhibition of calpain stabilises podosomes and impairs dendritic cell motility.
abstract: Podosomes, highly dynamic adhesion structures implicated in cell motility and extracellular matrix degradation, are characteristic of certain cells of the myeloid lineage and a limited range of other cell types. The nature and the mechanisms that regulate their high turnover are unknown at present. The cysteine protease calpain is involved in the regulation of cell migration in part by promoting either formation or disassembly of adhesion sites. Despite the fact that many known substrates of calpain are also structural components of the podosome complex, no studies have yet demonstrated that calpain participates in the regulation of podosome dynamics. In the present work, we show that inhibition of calpain in primary mouse dendritic cells leads to enhanced accumulation of actin filaments, the Wiskott Aldrich Syndrome protein (WASP), beta(2) integrins, talin, paxillin and vinculin in podosomes. This accumulation of components is associated with stabilisation of podosome turnover, overall reduction in velocity of cell locomotion and impaired transmigration across an endothelial monolayer. We also demonstrate that calpain cleaves the podosome components talin, Pyk2 and WASP in dendritic cells. In summary, our results provide evidence that calpain regulates podosome composition and turnover and that this process is required for efficient migration of dendritic cells.
authors.affiliation: Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guy's Campus, UK. yolanda.calle@kcl.ac.uk
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Calle
authors.forename: Neil O
authors.initials: NO
authors.lastname: Carragher
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Thrasher
authors.forename: Gareth E
authors.initials: GE
authors.lastname: Jones
mesh_terms: D008841:Actin Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure*; D000818:Animals; D002135:Calcium-Binding Proteins / Q000494:pharmacology; D002154:Calpain / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D021961:Cell Membrane Structures / Q000187:drug effects / Q000378:metabolism*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000502:physiology*; D004789:Enzyme Activation / Q000187:drug effects; D051418:Focal Adhesion Kinase 2 / Q000378:metabolism; D006023:Glycoproteins / Q000494:pharmacology; D051379:Mice; D008815:Mice, Inbred Strains; D009842:Oligopeptides / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D013329:Structure-Activity Relationship; D016608:Talin / Q000378:metabolism; D051316:Wiskott-Aldrich Syndrome Protein / Q000378:metabolism
chemical_list: D002135:Calcium-Binding Proteins; D006023:Glycoproteins; D009842:Oligopeptides; D010446:Peptide Fragments; D016608:Talin; C495768:Was protein, mouse; D051316:Wiskott-Aldrich Syndrome Protein; C039304:calpain inhibitors; C496077:Tln1 protein, mouse; C069861:calpain inhibitor 2; C033668:calpastatin; D051418:Focal Adhesion Kinase 2; C496053:Ptk2b protein, mouse; D002154:Calpain