The merlin tumor suppressor interacts with Ral guanine nucleotide dissociation stimulator and inhibits its activity

Neurofibromatosis type 2 (NF2) is the most commonly mutated gene in benign tumors of the human nervous system such as schwannomas and meningiomas. The NF2 gene encodes a protein called schwannomin or merlin, which is involved in regulating cell growth and proliferation through protein–protein interactions with various cellular proteins. In order to better understand the mechanism by which merlin exerts its function, yeast two-hybrid screening was performed and Ral guanine nucleotide dissociation stimulator (RalGDS), a downstream molecule of Ras, was identified as a merlin-binding protein. The direct interaction between merlin and RalGDS was confirmed both in vitro and in the NIH3T3 cells. The domain analyses revealed that the broad C-terminal region of merlin (aa 141–595) is necessary for the interaction with the C-terminal Ras-binding domain (RBD) of RalGDS. Functional studies showed that merlin inhibits the RalGDS-induced RalA activation, the colony formation and the cell migration in mammalian cells. These results suggest that merlin can function as a tumor suppressor by inhibiting the RalGDS-mediated oncogenic signals.

[1]  S. Pulst,et al.  Neurofibromatosis 2 tumour suppressor schwannomin interacts with βII-spectrin , 1998, Nature Genetics.

[2]  L. Feig,et al.  Regulation of Ras Signaling Specificity by Protein Kinase C , 2001, Molecular and Cellular Biology.

[3]  K. Hoang-Xuan,et al.  Neurofibromatosis type 2. , 1994, European journal of cancer.

[4]  D. Bar-Sagi,et al.  Ras effectors and their role in mitogenesis and oncogenesis , 1997, Journal of Molecular Medicine.

[5]  J. Haines,et al.  A novel moesin-, ezrin-, radixin-like gene is a candidate for the neurofibromatosis 2 tumor suppressor , 1993, Cell.

[6]  G. Rouleau,et al.  Schwannomin Isoform-1 Interacts with Syntenin via PDZ Domains* , 2001, The Journal of Biological Chemistry.

[7]  D. Gutmann,et al.  Protein 4.1 tumor suppressors: getting a FERM grip on growth regulation , 2002, Journal of Cell Science.

[8]  R. Wolthuis,et al.  Ras-dependent activation of the small GTPase Ral , 1998, Current Biology.

[9]  C. Haipek,et al.  The NF2 tumor suppressor gene product, merlin, mediates contact inhibition of growth through interactions with CD44. , 2001, Genes & development.

[10]  S. Pulst,et al.  Effects of Nf2 missense mutations on schwannomin interactions. , 2002, Biochemical and biophysical research communications.

[11]  Zhimin Lu,et al.  Phospholipase D and RalA Cooperate with the Epidermal Growth Factor Receptor To Transform 3Y1 Rat Fibroblasts , 2000, Molecular and Cellular Biology.

[12]  I. K. Lee,et al.  MAP, a protein interacting with a tumor suppressor, merlin, through the run domain. , 2004, Biochemical and biophysical research communications.

[13]  Li Guang,et al.  Involvement of Ras and Ral in Chemotactic Migration of Skeletal Myoblasts , 2000, Molecular and Cellular Biology.

[14]  Hongtae Kim,et al.  Merlin, a Tumor Suppressor, Interacts with Transactivation-responsive RNA-binding Protein and Inhibits Its Oncogenic Activity* , 2004, Journal of Biological Chemistry.

[15]  T. Jacks,et al.  Cellular transformation by a FERM domain mutant of the Nf2 tumor suppressor gene , 2002, Oncogene.

[16]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[17]  M. Nakao,et al.  Impairment of cell adhesion by expression of the mutant neurofibromatosis type 2 (NF2) genes which lack exons in the ERM-homology domain , 1998, Oncogene.

[18]  R. Schiestl,et al.  Improved method for high efficiency transformation of intact yeast cells. , 1992, Nucleic acids research.

[19]  T. Jacks,et al.  Mice heterozygous for a mutation at the Nf2 tumor suppressor locus develop a range of highly metastatic tumors. , 1998, Genes & development.

[20]  S. Pulst,et al.  Alteration in a new gene encoding a putative membrane-organizing protein causes neuro-fibromatosis type 2 , 1993, Nature.

[21]  S. Fields,et al.  Activated Ras interacts with the Ral guanine nucleotide dissociation stimulator. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[22]  T. Urano,et al.  An Eps Homology (EH) Domain Protein That Binds to the Ral-GTPase Target, RalBP1* , 1997, The Journal of Biological Chemistry.

[23]  M. Wigler,et al.  A Role for the Ral Guanine Nucleotide Dissociation Stimulator in Mediating Ras-induced Transformation* , 1996, The Journal of Biological Chemistry.

[24]  J. Gusella,et al.  Neuropathology and Molecular Genetics of Neurofibromatosis 2 and Related Tumors , 1995, Brain pathology.

[25]  E. Chiocca,et al.  Inhibition of NF2-negative and NF2-positive primary human meningioma cell proliferation by overexpression of merlin due to vector-mediated gene transfer. , 1999, Journal of neurosurgery.

[26]  S. C. Liu,et al.  The FERM domain: A unique module involved in the linkage of cytoplasmic proteins to the membrane , 1998 .

[27]  D. Gutmann,et al.  Interdomain binding mediates tumor growth suppression by the NF2 gene product , 1997, Oncogene.

[28]  Jacques Camonis,et al.  Cloning and Characterization of SCHIP-1, a Novel Protein Interacting Specifically with Spliced Isoforms and Naturally Occurring Mutant NF2 Proteins , 2000, Molecular and Cellular Biology.

[29]  Hongtae Kim,et al.  Inhibition of NF-κB activation by merlin , 2002 .

[30]  C. Der,et al.  Increasing Complexity of the Ras Signaling Pathway* , 1998, The Journal of Biological Chemistry.

[31]  Hongtae Kim,et al.  Merlin suppresses the SRE-dependent transcription by inhibiting the activation of Ras-ERK pathway. , 2003, Biochemical and biophysical research communications.

[32]  S. Tsukita,et al.  ERM proteins: head-to-tail regulation of actin-plasma membrane interaction. , 1997, Trends in biochemical sciences.

[33]  J. Gusella,et al.  NHE-RF, a Regulatory Cofactor for Na+-H+Exchange, Is a Common Interactor for Merlin and ERM (MERM) Proteins* , 1998, The Journal of Biological Chemistry.

[34]  A. Wittinghofer,et al.  Interactions between Ras proteins and their effectors. , 1996, Current opinion in biotechnology.

[35]  S. Pulst,et al.  The neurofibromatosis 2 tumor suppressor protein interacts with hepatocyte growth factor-regulated tyrosine kinase substrate. , 2000, Human molecular genetics.

[36]  M. Kressel,et al.  Nucleocytoplasmic transfer of the NF2 tumor suppressor protein merlin is regulated by exon 2 and a CRM1-dependent nuclear export signal in exon 15. , 2002, Human molecular genetics.

[37]  M. Matsuda,et al.  RalA activation at nascent lamellipodia of epidermal growth factor-stimulated Cos7 cells and migrating Madin-Darby canine kidney cells. , 2004, Molecular biology of the cell.

[38]  T. Hinoi,et al.  Identification and Characterization of a Novel Protein Interacting with Ral-binding Protein 1, a Putative Effector Protein of Ral* , 1998, The Journal of Biological Chemistry.

[39]  M. Kressel,et al.  Novel alternatively spliced isoforms of the neurofibromatosis type 2 tumor suppressor are targeted to the nucleus and cytoplasmic granules. , 1999, Human molecular genetics.

[40]  S. Cantor,et al.  Evidence for a Ras/Ral signaling cascade. , 1996, Trends in biochemical sciences.

[41]  Alma Rodenas-Ruano,et al.  Paxillin binds schwannomin and regulates its density-dependent localization and effect on cell morphology , 2002, Nature Genetics.