Tumor suppressors TSC1 and TSC2 differentially modulate actin cytoskeleton and motility of mouse embryonic fibroblasts
| Autor: | Vera P. Krymskaya, Melane L. James, Elena A. Goncharova, Dmitry A. Goncharov, Tatiana V. Kudryashova |
|---|---|
| Přispěvatelé: | Hotchin, Neil A |
| Rok vydání: | 2014 |
| Předmět: |
Cell signaling
RHOA Pulmonology lcsh:Medicine Actin Filaments Signal transduction mTORC2 Tuberous Sclerosis Complex 1 Protein Gene Knockout Techniques Mice 0302 clinical medicine Tuberous Sclerosis Cell Movement Stress Fibers Molecular Cell Biology Morphogenesis Medicine and Health Sciences 2.1 Biological and endogenous factors Aetiology RNA Small Interfering lcsh:Science Cytoskeleton 0303 health sciences Multidisciplinary TOR Serine-Threonine Kinases Cell migration Cell biology Cell Motility Actin Cytoskeleton Oncology Embryo 030220 oncology & carcinogenesis embryonic structures Cellular Structures and Organelles Research Article congenital hereditary and neonatal diseases and abnormalities Stress fiber General Science & Technology Biophysics Cell Migration Mechanistic Target of Rapamycin Complex 2 Biology Mechanistic Target of Rapamycin Complex 1 Small Interfering Cell Line 03 medical and health sciences Rare Diseases Tuberous Sclerosis Complex 2 Protein Genetics Animals GTPase signaling PI3K/AKT/mTOR pathway TOR signaling 030304 developmental biology Biology and life sciences Mammalian Tumor Suppressor Proteins lcsh:R Actin remodeling Correction Fibroblasts Actin cytoskeleton Embryo Mammalian Molecular biology Brain Disorders nervous system diseases Rapamycin-Insensitive Companion of mTOR Protein Cell movement signaling Multiprotein Complexes biology.protein RNA lcsh:Q Carrier Proteins Developmental Biology |
| Zdroj: | PLoS ONE PLoS ONE, Vol 9, Iss 10, p e111476 (2014) PloS one, vol 9, iss 10 |
| ISSN: | 1932-6203 |
| Popis: | TSC1 and TSC2 mutations cause neoplasms in rare disease pulmonary LAM and neuronal pathfinding in hamartoma syndrome TSC. The specific roles of TSC1 and TSC2 in actin remodeling and the modulation of cell motility, however, are not well understood. Previously, we demonstrated that TSC1 and TSC2 regulate the activity of small GTPases RhoA and Rac1, stress fiber formation and cell adhesion in a reciprocal manner. Here, we show that Tsc1(-/-) MEFs have decreased migration compared to littermate-derived Tsc1(+/+) MEFs. Migration of Tsc1(-/-) MEFs with re-expressed TSC1 was comparable to Tsc1(+/+) MEF migration. In contrast, Tsc2(-/-) MEFs showed an increased migration compared to Tsc2(+/+) MEFs that were abrogated by TSC2 re-expression. Depletion of TSC1 and TSC2 using specific siRNAs in wild type MEFs and NIH 3T3 fibroblasts also showed that TSC1 loss attenuates cell migration while TSC2 loss promotes cell migration. Morphological and immunochemical analysis demonstrated that Tsc1(-/-) MEFs have a thin protracted shape with a few stress fibers; in contrast, Tsc2(-/-) MEFs showed a rounded morphology and abundant stress fibers. Expression of TSC1 in either Tsc1(-/-) or Tsc2(-/-) MEFs promoted stress fiber formation, while TSC2 re-expression induced stress fiber disassembly and the formation of cortical actin. To assess the mechanism(s) by which TSC2 loss promotes actin re-arrangement and cell migration, we explored the role of known downstream effectors of TSC2, mTORC1 and mTORC2. Increased migration of Tsc2(-/-) MEFs is inhibited by siRNA mTOR and siRNA Rictor, but not siRNA Raptor. siRNA mTOR or siRNA Rictor promoted stress fiber disassembly in TSC2-null cells, while siRNA Raptor had little effect. Overexpression of kinase-dead mTOR induced actin stress fiber disassembly and suppressed TSC2-deficient cell migration. Our data demonstrate that TSC1 and TSC2 differentially regulate actin stress fiber formation and cell migration, and that only TSC2 loss promotes mTOR- and mTORC2-dependent pro-migratory cell phenotype. |
| Databáze: | OpenAIRE |
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