title: Tensin 2 modulates cell contractility in 3D collagen gels through the RhoGAP DLC1.
abstract: Cytoskeletal proteins of the tensin family couple integrins to the actin cytoskeleton. They are found in both focal adhesions and the fibrillar adhesions formed between cells and the fibronectin matrix. There are four tensin genes which encode three large (approximately 200 kDa) tensin isoforms (tensin 1, 2, 3) and one short isoform (cten). However, the subcellular localization and function of the individual isoforms is poorly understood. Using human foreskin fibroblasts (HFFs), and imaging on both fixed and live cells, we show that GFP-tensin 2 is enriched in dynamic focal adhesions at the leading edge of the cell, whereas GFP-tensin 3 translocates rearward, and is enriched in fibrillar adhesions. To investigate the possible role of tensins in cell-matrix remodeling, we used siRNAs to knockdown each tensin isoform. We discovered that tensin 2 knockdown significantly reduced the ability of HFFs to contract 3D collagen gels, whilst no effect on fibronectin fibrillogenesis was observed. This inhibition of collagen gel contraction was associated with a substantial reduction in Rho activity, and it was reversed by depletion of DLC1, a RhoGAP that binds to tensin in focal adhesions. These findings suggest that focal adhesion-localized tensin 2 negatively regulates DLC1 to permit Rho-mediated actomyosin contraction and remodeling of collagen fibers.
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester, UK.
authors.forename: Katherine
authors.initials: K
authors.lastname: Clark
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Howe
authors.forename: Christine E
authors.initials: CE
authors.lastname: Pullar
authors.forename: J Angelo
authors.initials: JA
authors.lastname: Green
authors.forename: Vira V
authors.initials: VV
authors.lastname: Artym
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Yamada
authors.forename: David R
authors.initials: DR
authors.lastname: Critchley
mesh_terms: D000205:Actomyosin / Q000378:metabolism; D002448:Cell Adhesion; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D003599:Cytoskeleton / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology*; D022001:Focal Adhesions / Q000737:chemistry; D020690:GTPase-Activating Proteins / Q000235:genetics*; D005782:Gels; D006801:Humans; D008840:Microfilament Proteins / Q000032:analysis / Q000502:physiology*; D009068:Movement; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis / Q000502:physiology*; D034741:RNA, Small Interfering / Q000494:pharmacology; D000070876:Tensins; D025521:Tumor Suppressor Proteins / Q000235:genetics*; D015854:Up-Regulation / Q000235:genetics
chemical_list: C112352:DLC1 protein, human; D020690:GTPase-Activating Proteins; D005782:Gels; D008840:Microfilament Proteins; D034741:RNA, Small Interfering; D000070876:Tensins; D025521:Tumor Suppressor Proteins; D003094:Collagen; D000205:Actomyosin; C452816:TNS2 protein, human; D010744:Phosphoric Monoester Hydrolases