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Case LB, Baird MA, Shtengel G, Campbell SL, Hess HF, Davidson MW, Waterman CM. Molecular mechanism of vinculin activation and nanoscale spatial organization in focal adhesions. Nat Cell Biol 2015; 17:880-92. [PMID: 26053221 PMCID: PMC4490039 DOI: 10.1038/ncb3180] [Citation(s) in RCA: 201] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 04/23/2015] [Indexed: 12/13/2022]
Abstract
Focal adhesions (FAs) link the extracellular matrix (ECM) to the actin cytoskeleton to mediate cell adhesion, migration, mechanosensing and signaling. FAs have conserved nanoscale protein organization, suggesting that the position of proteins within FAs regulates their activity and function. Vinculin binds different FA proteins to mediate distinct cellular functions, but how vinculin’s interactions are spatiotemporally organized within FA is unknown. Using interferometric photo-activation localization (iPALM) super-resolution microscopy to assay vinculin nanoscale localization and a FRET biosensor to assay vinculin conformation, we found that upward repositioning within the FA during FA maturation facilitates vinculin activation and mechanical reinforcement of FA. Inactive vinculin localizes to the lower integrin signaling layer in FA by binding to phospho-paxillin. Talin binding activates vinculin and targets active vinculin higher in FA where vinculin can engage retrograde actin flow. Thus, specific protein interactions are spatially segregated within FA at the nano-scale to regulate vinculin activation and function.
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Affiliation(s)
- Lindsay B Case
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Michelle A Baird
- National High Magnetic Field Laboratory and Department of Biological Science, The Florida State University, Tallahassee, Florida 32310, USA
| | - Gleb Shtengel
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147, USA
| | - Sharon L Campbell
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Harald F Hess
- Howard Hughes Medical Institute, Janelia Farm Research Campus, Ashburn, Virginia 20147, USA
| | - Michael W Davidson
- National High Magnetic Field Laboratory and Department of Biological Science, The Florida State University, Tallahassee, Florida 32310, USA
| | - Clare M Waterman
- Cell Biology and Physiology Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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152
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Nelson DA, Larsen M. Heterotypic control of basement membrane dynamics during branching morphogenesis. Dev Biol 2015; 401:103-9. [PMID: 25527075 PMCID: PMC4465071 DOI: 10.1016/j.ydbio.2014.12.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/24/2014] [Accepted: 12/09/2014] [Indexed: 02/06/2023]
Abstract
Many mammalian organs undergo branching morphogenesis to create highly arborized structures with maximized surface area for specialized organ function. Cooperative cell-cell and cell-matrix adhesions that sculpt the emerging tissue architecture are guided by dynamic basement membranes. Properties of the basement membrane are reciprocally controlled by the interacting epithelial and mesenchymal cell populations. Here we discuss how basement membrane remodeling is required for branching morphogenesis to regulate cell-matrix and cell-cell adhesions that are required for cell patterning during morphogenesis and how basement membrane impacts morphogenesis by stimulation of cell patterning, force generation, and mechanotransduction. We suggest that in addition to creating mature epithelial architecture, remodeling of the epithelial basement membrane during branching morphogenesis is also essential to promote maturation of the stromal mesenchyme to create mature organ structure. Recapitulation of developmental cell-matrix and cell-cell interactions are of critical importance in tissue engineering and regeneration strategies that seek to restore organ function.
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Affiliation(s)
- Deirdre A Nelson
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, 1400 Washington Ave, Albany, NY 12222, USA
| | - Melinda Larsen
- Department of Biological Sciences, University at Albany, State University of New York, 1400 Washington Avenue, 1400 Washington Ave, Albany, NY 12222, USA.
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153
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PI3K/Akt signaling in osteosarcoma. Clin Chim Acta 2015; 444:182-92. [PMID: 25704303 DOI: 10.1016/j.cca.2014.12.041] [Citation(s) in RCA: 235] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Revised: 11/24/2014] [Accepted: 12/09/2014] [Indexed: 12/19/2022]
Abstract
Osteosarcoma (OS) is the most common nonhematologic bone malignancy in children and adolescents. Despite the advances of adjuvant chemotherapy and significant improvement of survival, the prognosis remains generally poor. As such, the search for more effective anti-OS agents is urgent. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is thought to be one of the most important oncogenic pathways in human cancer. An increasing body of evidence has shown that this pathway is frequently hyperactivated in OS and contributes to disease initiation and development, including tumorigenesis, proliferation, invasion, cell cycle progression, inhibition of apoptosis, angiogenesis, metastasis and chemoresistance. Inhibition of this pathway through small molecule compounds represents an attractive potential therapeutic approach for OS. The aim of this review is to summarize the roles of the PI3K/Akt pathway in the development and progression of OS, and to highlight the therapeutic potential of targeting this signaling pathway. Knowledge obtained from the application of these compounds will help in further understanding the pathogenesis of OS and designing subsequent treatment strategies.
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154
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Cassereau L, Miroshnikova YA, Ou G, Lakins J, Weaver VM. A 3D tension bioreactor platform to study the interplay between ECM stiffness and tumor phenotype. J Biotechnol 2014; 193:66-9. [PMID: 25435379 DOI: 10.1016/j.jbiotec.2014.11.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 11/05/2014] [Accepted: 11/07/2014] [Indexed: 02/01/2023]
Abstract
Extracellular matrix (ECM) structure, composition, and stiffness have profound effects on tissue development and pathologies such as cardiovascular disease and cancer. Accordingly, a variety of synthetic hydrogel systems have been designed to study the impact of ECM composition, density, mechanics, and topography on cell and tissue phenotype. However, these synthetic systems fail to accurately recapitulate the biological properties and structure of the native tissue ECM. Natural three dimensional (3D) ECM hydrogels, such as collagen or hyaluronic acid, feature many of the chemical and physical properties of tissue, yet, these systems have limitations including the inability to independently control biophysical properties such as stiffness and pore size. Here, we present a 3D tension bioreactor system that permits precise mechanical tuning of collagen hydrogel stiffness, while maintaining consistent composition and pore size. We achieve this by mechanically loading collagen hydrogels covalently-conjugated to a polydimethylsiloxane (PDMS) membrane to induce hydrogel stiffening. We validated the biological application of this system with oncogenically transformed mammary epithelial cell organoids embedded in a 3D collagen I hydrogel, either uniformly stiffened or calibrated to create a gradient of ECM stiffening, to visually demonstrate the impact of ECM stiffening on transformation and tumor cell invasion. As such, this bioreactor presents the first tunable 3D natural hydrogel system that is capable of independently assessing the role of ECM stiffness on tissue phenotype.
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Affiliation(s)
- Luke Cassereau
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, CA, USA; University of California San Francisco/University of California Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, USA
| | - Yekaterina A Miroshnikova
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, CA, USA; University of California San Francisco/University of California Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, USA
| | - Guanqing Ou
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, CA, USA; University of California San Francisco/University of California Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA, USA
| | - Johnathon Lakins
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, CA, USA
| | - Valerie M Weaver
- Center for Bioengineering and Tissue Regeneration, Department of Surgery, UCSF, San Francisco, CA, USA; Department of Anatomy, and Department of Bioengineering and Therapeutic Sciences, UCSF, San Francisco, CA, USA; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, UCSF, San Francisco, CA, USA; UCSF Helen Diller Comprehensive Cancer Center, UCSF, San Francisco, CA, USA.
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