The Neurofibromatosis Type 2 Gene Product, merlin, Reverses the F-Actin Cytoskeletal Defects in Primary Human Schwannoma Cells
Open Access
- 1 February 2002
- journal article
- Published by Informa UK Limited in Molecular and Cellular Biology
- Vol. 22 (4), 1150-1157
- https://doi.org/10.1128/mcb.22.4.1150-1157.2002
Abstract
Schwannoma tumors, which occur sporadically and in patients with neurofibromatosis, account for 8% of intracranial tumors and can only be treated by surgical removal. Most schwannomas have biallelic mutations in the NF2 tumor suppressor gene. We previously showed that schwannoma-derived Schwann cells exhibit membrane ruffling and aberrant cell spreading when plated onto laminin, indicative of fundamental F-actin cytoskeletal defects. Here we expand these observations to a large group of sporadic and NF2-related tumors and extend them to schwannomatosis-derived tumors. Mutation at NF2 correlated with F-actin abnormalities, but the extent of morphological change did not correlate with the type of NF2 mutation. We used a recently described molecular strategy, TAT-mediated protein transfer, to acutely introduce the NF2 protein, merlin, into primary human schwannoma cells in an attempt to reverse the cytoskeletal phenotype. Abnormal ruffling and cell spreading by cells with identified NF2 mutations were rapidly reversed by introduction of TAT-merlin. The effect is specific to TAT-merlin isoform 1, the growth-suppressive isoform of merlin. TAT-merlin isoform 2, a TAT-merlin mutant (L64P), and merlin lacking TAT were ineffective in reversing the cytoskeletal phenotype. Results show that merlin isoform 1 is sufficient to restore normal actin organization in NF2-deficient human tumor cells, demonstrating a key role for merlin in the NF2 phenotype. These results lay the foundation for epigenetic complementation studies in NF2 mouse models and possibly for experiments to evaluate the utility of merlin transduction into patients as protein therapy.Keywords
This publication has 49 references indexed in Scilit:
- Hierarchy of Merlin and Ezrin N- and C-terminal Domain Interactions in Homo- and Heterotypic Associations and Their Relationship to Binding of Scaffolding Proteins EBP50 and E3KARPJournal of Biological Chemistry, 2001
- ERM-Merlin and EBP50 Protein Families in Plasma Membrane Organization and FunctionAnnual Review of Cell and Developmental Biology, 2000
- Functional Analysis of the Neurofibromatosis Type 2 Protein by Means of Disease-Causing Point MutationsAmerican Journal of Human Genetics, 2000
- Expression level, subcellular distribution and Rho-GDI binding affinity of merlin in comparison with ezrin/radixin/moesin proteinsOncogene, 1999
- Transduction of full-length TAT fusion proteins into mammalian cells: TAT-p27Kip1 induces cell migrationNature Medicine, 1998
- Ruffling membrane, stress fiber, cell spreading and proliferation abnormalities in human Schwannoma cellsOncogene, 1998
- Isolation and Characterization of Schwann Cells from Neurofibromatosis Type 2 PatientsNeurobiology of Disease, 1998
- Merlin Differs from Moesin in Binding to F-Actin and in Its Intra- and Intermolecular InteractionsBiochemical and Biophysical Research Communications, 1998
- Molecular Analysis of the NF2 Tumor-Suppressor Gene in SchwannomatosisAmerican Journal of Human Genetics, 1997
- The small GTP-binding protein rac regulates growth factor-induced membrane rufflingCell, 1992