Skip to main content
NCBI home page
The Journal of Cell Biology logoLink to The Journal of Cell Biology
. 1996 May 2;133(4):843–852. doi: 10.1083/jcb.133.4.843

Distinct cellular and subcellular patterns of expression imply distinct functions for the Drosophila homologues of moesin and the neurofibromatosis 2 tumor suppressor, merlin

PMCID: PMC2120840  PMID: 8666669

Abstract

Interest in members of the protein 4.1 super-family, which includes the ezrin-radixin-moesin (ERM) group, has been stimulated recently by the discovery that the human neurofibromatosis 2 (NF2) tumor suppressor gene encodes an ERM-like protein, merlin. Although many proteins in this family are thought to act by linking the actin-based cytoskeleton to transmembrane proteins, the cellular functions of merlin have not been defined. To investigate the cellular and developmental functions of these proteins, we have identified and characterized Drosophila homologues of moesin (Dmoesin) and of the NF2 tumor suppressor merlin (Dmerlin). Using specific antibodies, we show that although these proteins are frequently coexpressed in developing tissues, they display distinct subcellular localizations. While Dmoesin is observed in continuous association with the plasma membrane, as is typical for an ERM family protein, Dmerlin is found in punctuate structures at the membrane and in the cytoplasm. Investigation of Dmerlin cultured cells demonstrates that it is associated with endocytic compartments. As a result of these studies, we propose that the merlin protein has unique functions in the cell which differ from those of other ERM family members.

Full Text

The Full Text of this article is available as a PDF (4.0 MB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Algrain M., Turunen O., Vaheri A., Louvard D., Arpin M. Ezrin contains cytoskeleton and membrane binding domains accounting for its proposed role as a membrane-cytoskeletal linker. J Cell Biol. 1993 Jan;120(1):129–139. doi: 10.1083/jcb.120.1.129. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Altschul S. F., Gish W., Miller W., Myers E. W., Lipman D. J. Basic local alignment search tool. J Mol Biol. 1990 Oct 5;215(3):403–410. doi: 10.1016/S0022-2836(05)80360-2. [DOI] [PubMed] [Google Scholar]
  3. Banerjee U., Renfranz P. J., Hinton D. R., Rabin B. A., Benzer S. The sevenless+ protein is expressed apically in cell membranes of developing Drosophila retina; it is not restricted to cell R7. Cell. 1987 Oct 9;51(1):151–158. doi: 10.1016/0092-8674(87)90020-1. [DOI] [PubMed] [Google Scholar]
  4. Banville D., Ahmad S., Stocco R., Shen S. H. A novel protein-tyrosine phosphatase with homology to both the cytoskeletal proteins of the band 4.1 family and junction-associated guanylate kinases. J Biol Chem. 1994 Sep 2;269(35):22320–22327. [PubMed] [Google Scholar]
  5. Bennett V. Spectrin-based membrane skeleton: a multipotential adaptor between plasma membrane and cytoplasm. Physiol Rev. 1990 Oct;70(4):1029–1065. doi: 10.1152/physrev.1990.70.4.1029. [DOI] [PubMed] [Google Scholar]
  6. Berryman M., Franck Z., Bretscher A. Ezrin is concentrated in the apical microvilli of a wide variety of epithelial cells whereas moesin is found primarily in endothelial cells. J Cell Sci. 1993 Aug;105(Pt 4):1025–1043. doi: 10.1242/jcs.105.4.1025. [DOI] [PubMed] [Google Scholar]
  7. Bretscher A. Purification of an 80,000-dalton protein that is a component of the isolated microvillus cytoskeleton, and its localization in nonmuscle cells. J Cell Biol. 1983 Aug;97(2):425–432. doi: 10.1083/jcb.97.2.425. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Bretscher A. Rapid phosphorylation and reorganization of ezrin and spectrin accompany morphological changes induced in A-431 cells by epidermal growth factor. J Cell Biol. 1989 Mar;108(3):921–930. doi: 10.1083/jcb.108.3.921. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Brown N. H., Kafatos F. C. Functional cDNA libraries from Drosophila embryos. J Mol Biol. 1988 Sep 20;203(2):425–437. doi: 10.1016/0022-2836(88)90010-1. [DOI] [PubMed] [Google Scholar]
  10. Bunch T. A., Grinblat Y., Goldstein L. S. Characterization and use of the Drosophila metallothionein promoter in cultured Drosophila melanogaster cells. Nucleic Acids Res. 1988 Feb 11;16(3):1043–1061. doi: 10.1093/nar/16.3.1043. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. DiMario P. J., Mahowald A. P. Female sterile (1) yolkless: a recessive female sterile mutation in Drosophila melanogaster with depressed numbers of coated pits and coated vesicles within the developing oocytes. J Cell Biol. 1987 Jul;105(1):199–206. doi: 10.1083/jcb.105.1.199. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. DiMario P. J., Mahowald A. P. The effects of pH and weak bases on the in vitro endocytosis of vitellogenin by oocytes of Drosophila melanogaster. Cell Tissue Res. 1986;246(1):103–108. doi: 10.1007/BF00219005. [DOI] [PubMed] [Google Scholar]
  13. Edwards K. A., Montague R. A., Shepard S., Edgar B. A., Erikson R. L., Kiehart D. P. Identification of Drosophila cytoskeletal proteins by induction of abnormal cell shape in fission yeast. Proc Natl Acad Sci U S A. 1994 May 10;91(10):4589–4593. doi: 10.1073/pnas.91.10.4589. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Fehon R. G., Dawson I. A., Artavanis-Tsakonas S. A Drosophila homologue of membrane-skeleton protein 4.1 is associated with septate junctions and is encoded by the coracle gene. Development. 1994 Mar;120(3):545–557. doi: 10.1242/dev.120.3.545. [DOI] [PubMed] [Google Scholar]
  15. Fehon R. G., Johansen K., Rebay I., Artavanis-Tsakonas S. Complex cellular and subcellular regulation of notch expression during embryonic and imaginal development of Drosophila: implications for notch function. J Cell Biol. 1991 May;113(3):657–669. doi: 10.1083/jcb.113.3.657. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Fehon R. G., Kooh P. J., Rebay I., Regan C. L., Xu T., Muskavitch M. A., Artavanis-Tsakonas S. Molecular interactions between the protein products of the neurogenic loci Notch and Delta, two EGF-homologous genes in Drosophila. Cell. 1990 May 4;61(3):523–534. doi: 10.1016/0092-8674(90)90534-l. [DOI] [PubMed] [Google Scholar]
  17. Franck Z., Gary R., Bretscher A. Moesin, like ezrin, colocalizes with actin in the cortical cytoskeleton in cultured cells, but its expression is more variable. J Cell Sci. 1993 May;105(Pt 1):219–231. doi: 10.1242/jcs.105.1.219. [DOI] [PubMed] [Google Scholar]
  18. Frorath B., Scanarini M., Netter H. J., Abney C. C., Liedvogel B., Lakomek H. J., Northemann W. Cloning and expression of antigenic epitopes of the human 68-kDa (U1) ribonucleoprotein antigen in Escherichia coli. Biotechniques. 1991 Sep;11(3):364-6, 368-71. [PubMed] [Google Scholar]
  19. Funayama N., Nagafuchi A., Sato N., Tsukita S., Tsukita S. Radixin is a novel member of the band 4.1 family. J Cell Biol. 1991 Nov;115(4):1039–1048. doi: 10.1083/jcb.115.4.1039. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Gould K. L., Bretscher A., Esch F. S., Hunter T. cDNA cloning and sequencing of the protein-tyrosine kinase substrate, ezrin, reveals homology to band 4.1. EMBO J. 1989 Dec 20;8(13):4133–4142. doi: 10.1002/j.1460-2075.1989.tb08598.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Greenwald I., Rubin G. M. Making a difference: the role of cell-cell interactions in establishing separate identities for equivalent cells. Cell. 1992 Jan 24;68(2):271–281. doi: 10.1016/0092-8674(92)90470-w. [DOI] [PubMed] [Google Scholar]
  22. Gu M. X., York J. D., Warshawsky I., Majerus P. W. Identification, cloning, and expression of a cytosolic megakaryocyte protein-tyrosine-phosphatase with sequence homology to cytoskeletal protein 4.1. Proc Natl Acad Sci U S A. 1991 Jul 1;88(13):5867–5871. doi: 10.1073/pnas.88.13.5867. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Lankes W. T., Furthmayr H. Moesin: a member of the protein 4.1-talin-ezrin family of proteins. Proc Natl Acad Sci U S A. 1991 Oct 1;88(19):8297–8301. doi: 10.1073/pnas.88.19.8297. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. MacCollin M., Mohney T., Trofatter J., Wertelecki W., Ramesh V., Gusella J. DNA diagnosis of neurofibromatosis 2. Altered coding sequence of the merlin tumor suppressor in an extended pedigree. JAMA. 1993 Nov 17;270(19):2316–2320. doi: 10.1001/jama.270.19.2316. [DOI] [PubMed] [Google Scholar]
  25. Martuza R. L., Eldridge R. Neurofibromatosis 2 (bilateral acoustic neurofibromatosis). N Engl J Med. 1988 Mar 17;318(11):684–688. doi: 10.1056/NEJM198803173181106. [DOI] [PubMed] [Google Scholar]
  26. Mays R. W., Beck K. A., Nelson W. J. Organization and function of the cytoskeleton in polarized epithelial cells: a component of the protein sorting machinery. Curr Opin Cell Biol. 1994 Feb;6(1):16–24. doi: 10.1016/0955-0674(94)90111-2. [DOI] [PubMed] [Google Scholar]
  27. Miller K. G., Field C. M., Alberts B. M. Actin-binding proteins from Drosophila embryos: a complex network of interacting proteins detected by F-actin affinity chromatography. J Cell Biol. 1989 Dec;109(6 Pt 1):2963–2975. doi: 10.1083/jcb.109.6.2963. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Peifer M. The product of the Drosophila segment polarity gene armadillo is part of a multi-protein complex resembling the vertebrate adherens junction. J Cell Sci. 1993 Aug;105(Pt 4):993–1000. doi: 10.1242/jcs.105.4.993. [DOI] [PubMed] [Google Scholar]
  29. Poodry C. A. shibire, a neurogenic mutant of Drosophila. Dev Biol. 1990 Apr;138(2):464–472. doi: 10.1016/0012-1606(90)90212-2. [DOI] [PubMed] [Google Scholar]
  30. Rees D. J., Ades S. E., Singer S. J., Hynes R. O. Sequence and domain structure of talin. Nature. 1990 Oct 18;347(6294):685–689. doi: 10.1038/347685a0. [DOI] [PubMed] [Google Scholar]
  31. Rouleau G. A., Merel P., Lutchman M., Sanson M., Zucman J., Marineau C., Hoang-Xuan K., Demczuk S., Desmaze C., Plougastel B. Alteration in a new gene encoding a putative membrane-organizing protein causes neuro-fibromatosis type 2. Nature. 1993 Jun 10;363(6429):515–521. doi: 10.1038/363515a0. [DOI] [PubMed] [Google Scholar]
  32. Sato N., Funayama N., Nagafuchi A., Yonemura S., Tsukita S., Tsukita S. A gene family consisting of ezrin, radixin and moesin. Its specific localization at actin filament/plasma membrane association sites. J Cell Sci. 1992 Sep;103(Pt 1):131–143. doi: 10.1242/jcs.103.1.131. [DOI] [PubMed] [Google Scholar]
  33. Smith D. B., Johnson K. S. Single-step purification of polypeptides expressed in Escherichia coli as fusions with glutathione S-transferase. Gene. 1988 Jul 15;67(1):31–40. doi: 10.1016/0378-1119(88)90005-4. [DOI] [PubMed] [Google Scholar]
  34. Swanson J. Fluorescent labeling of endocytic compartments. Methods Cell Biol. 1989;29:137–151. doi: 10.1016/s0091-679x(08)60192-2. [DOI] [PubMed] [Google Scholar]
  35. Takeuchi K., Sato N., Kasahara H., Funayama N., Nagafuchi A., Yonemura S., Tsukita S., Tsukita S. Perturbation of cell adhesion and microvilli formation by antisense oligonucleotides to ERM family members. J Cell Biol. 1994 Jun;125(6):1371–1384. doi: 10.1083/jcb.125.6.1371. [DOI] [PMC free article] [PubMed] [Google Scholar]
  36. Trofatter J. A., MacCollin M. M., Rutter J. L., Murrell J. R., Duyao M. P., Parry D. M., Eldridge R., Kley N., Menon A. G., Pulaski K. A novel moesin-, ezrin-, radixin-like gene is a candidate for the neurofibromatosis 2 tumor suppressor. Cell. 1993 Mar 12;72(5):791–800. doi: 10.1016/0092-8674(93)90406-g. [DOI] [PubMed] [Google Scholar]
  37. Tsukita S., Hieda Y., Tsukita S. A new 82-kD barbed end-capping protein (radixin) localized in the cell-to-cell adherens junction: purification and characterization. J Cell Biol. 1989 Jun;108(6):2369–2382. doi: 10.1083/jcb.108.6.2369. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Turunen O., Wahlström T., Vaheri A. Ezrin has a COOH-terminal actin-binding site that is conserved in the ezrin protein family. J Cell Biol. 1994 Sep;126(6):1445–1453. doi: 10.1083/jcb.126.6.1445. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Wells A., Welsh J. B., Lazar C. S., Wiley H. S., Gill G. N., Rosenfeld M. G. Ligand-induced transformation by a noninternalizing epidermal growth factor receptor. Science. 1990 Feb 23;247(4945):962–964. doi: 10.1126/science.2305263. [DOI] [PubMed] [Google Scholar]
  40. Yang Q., Tonks N. K. Isolation of a cDNA clone encoding a human protein-tyrosine phosphatase with homology to the cytoskeletal-associated proteins band 4.1, ezrin, and talin. Proc Natl Acad Sci U S A. 1991 Jul 15;88(14):5949–5953. doi: 10.1073/pnas.88.14.5949. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Zak N. B., Shilo B. Z. Localization of DER and the pattern of cell divisions in wild-type and Ellipse eye imaginal discs. Dev Biol. 1992 Feb;149(2):448–456. doi: 10.1016/0012-1606(92)90299-v. [DOI] [PubMed] [Google Scholar]
  42. van der Bliek A. M., Meyerowitz E. M. Dynamin-like protein encoded by the Drosophila shibire gene associated with vesicular traffic. Nature. 1991 May 30;351(6325):411–414. doi: 10.1038/351411a0. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press

RESOURCES