title: Involvement of YAP, TAZ and HSP90 in contact guidance and intercellular junction formation in corneal epithelial cells.
abstract: The extracellular environment possesses a rich milieu of biophysical and biochemical signaling cues that are simultaneously integrated by cells and influence cellular phenotype. Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (WWTR1; TAZ), two important signaling molecules of the Hippo pathway, have been recently implicated as nuclear relays of cytoskeletal changes mediated by substratum rigidity and topography. These proteins intersect with other important intracellular signaling pathways (e.g. Wnt and TGFβ). In the cornea, epithelial cells adhere to the stroma through a 3-dimensional topography-rich basement membrane, with features in the nano-submicron size-scale that are capable of profoundly modulating a wide range of fundamental cell behaviors. The influences of substratum-topography, YAP/TAZ knockdown, and HSP90 inhibition on cell morphology, YAP/TAZ localization, and the expression of TGFβ2 and CTGF, were investigated. The results demonstrate (a) that knockdown of TAZ enhances contact guidance in a YAP dependent manner, (b) that CTGF is predominantly regulated by YAP and not TAZ, and (c) that TGFβ2 is regulated by both YAP and TAZ in these cells. Additionally, inhibition of HSP90 resulted in nuclear localization and subsequent transcriptional-activation of YAP, formation of cell-cell junctions and co-localization of E-cadherin and β-catenin at adherens junctions. Results presented in this study reflect the complexities underlying the molecular relationships between the cytoskeleton, growth factors, heat shock proteins, and co-activators of transcription that impact mechanotransduction. The data reveal the importance of YAP/TAZ on the cell behaviors, and gene and protein expression.
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Vijay Krishna
authors.initials: VK
authors.lastname: Raghunathan
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Britta
authors.initials: B
authors.lastname: Dreier
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Joshua T
authors.initials: JT
authors.lastname: Morgan
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Binh C
authors.initials: BC
authors.lastname: Tuyen
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Brad W
authors.initials: BW
authors.lastname: Rose
authors.affiliation: Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Reilly
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Paul
authors.initials: P
authors.lastname: Russell
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America; Department of Ophthalmology & Vision Science, School of Medicine, University of California Davis, Davis, CA, United States of America.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Murphy
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016227:Benzoquinones / Q000494:pharmacology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D003315:Cornea / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007365:Intercellular Junctions / Q000187:drug effects / Q000648:ultrastructure; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D040542:Mechanotransduction, Cellular; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D061251:Primary Cell Culture; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators; D014157:Transcription Factors; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D053781:Transforming Growth Factor beta2 / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism; D000091102:YAP-Signaling Proteins; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D016227:Benzoquinones; C495270:CTNNB1 protein, human; D015820:Cadherins; D018841:HSP90 Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; D047029:Lactams, Macrocyclic; D010750:Phosphoproteins; D034741:RNA, Small Interfering; D015534:Trans-Activators; D014157:Transcription Factors; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D053781:Transforming Growth Factor beta2; C551991:WWTR1 protein, human; D051153:Wnt Proteins; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human; D051176:beta Catenin; C112765:tanespimycin