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. 1991 Oct 2;115(2):397–410. doi: 10.1083/jcb.115.2.397

Filensin: a new vimentin-binding, polymerization-competent, and membrane-associated protein of the lens fiber cell

PMCID: PMC2289143  PMID: 1918147

Abstract

We have studied the molecular properties of a 100-kD protein, termed filensin, which we have isolated from porcine lens membranes. Filensin represents a membrane-associated element, resistant to salt and nonionic detergent treatment, and extractable only by alkali or high concentrations of urea. By indirect immunofluorescence and immunoelectron microscopy, this protein can be localized at the periphery of the lens fiber cells. Immunochemical analysis suggests that filensin originates from a larger 110-kD component which is abundantly expressed in lens but not in other tissues. Purified filensin polymerizes in a salt-dependent fashion and forms irregular fibrils (integral of 10 nm in diameter) when reconstituted into buffers of physiological ionic strength and neutral pH. Radiolabeled filensin binds specifically to lens vimentin under isotonic conditions, as demonstrated by affinity chromatography and ligand-blotting assays. By the latter approach, filensin also reacts with a 47-kD peripheral membrane protein of the lens cells. Purified filensin binds to PI, a synthetic peptide modelled after a segment of the COOH-terminal domain of peripherin (a type III intermediate filament protein highly homologous to vimentin), but not to various other peptides including the NH2-terminal headpiece of vimentin and derivatives of its middle (rod) domain. The filensin-PI binding is inhibited by purified lamin B, which is known to interact in vitro with PI (Djabali, K., M.-M. Portier, F. Gros, G. Blobel, and S. D. Georgatos. 1991. Cell. 64:109- 121). Finally, limited proteolysis indicates that the filensin-vimentin interaction involves a 30-kD segment of the filensin molecule. Based on these observations, we postulate that the lens fiber cells express a polymerization-competent protein which is tightly associated with the plasma membrane and has the potential to serve as an anchorage site for vimentin intermediate filaments.

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Selected References

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  1. Albers K., Fuchs E. Expression of mutant keratin cDNAs in epithelial cells reveals possible mechanisms for initiation and assembly of intermediate filaments. J Cell Biol. 1989 Apr;108(4):1477–1493. doi: 10.1083/jcb.108.4.1477. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Albers K., Fuchs E. The expression of mutant epidermal keratin cDNAs transfected in simple epithelial and squamous cell carcinoma lines. J Cell Biol. 1987 Aug;105(2):791–806. doi: 10.1083/jcb.105.2.791. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Allen D. P., Low P. S., Dola A., Maisel H. Band 3 and ankyrin homologues are present in eye lens: evidence for all major erythrocyte membrane components in same non-erythroid cell. Biochem Biophys Res Commun. 1987 Nov 30;149(1):266–275. doi: 10.1016/0006-291x(87)91634-2. [DOI] [PubMed] [Google Scholar]
  4. Aster J. C., Brewer G. J., Maisel H. The 4.1-like proteins of the bovine lens: spectrin-binding proteins closely related in structure to red blood cell protein 4.1. J Cell Biol. 1986 Jul;103(1):115–122. doi: 10.1083/jcb.103.1.115. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Bloemendal H. Lens proteins. CRC Crit Rev Biochem. 1982;12(1):1–38. doi: 10.3109/10409238209105849. [DOI] [PubMed] [Google Scholar]
  6. Bloemendal H., Zweers A., Vermorken F., Dunia I., Benedetti E. L. The plasma membranes of eye lens fibres. Biochemical and structural characterization. Cell Differ. 1972 Jun;1(2):91–106. doi: 10.1016/0045-6039(72)90032-2. [DOI] [PubMed] [Google Scholar]
  7. Cartaud A., Courvalin J. C., Ludosky M. A., Cartaud J. Presence of a protein immunologically related to lamin B in the postsynaptic membrane of Torpedo marmorata electrocyte. J Cell Biol. 1989 Oct;109(4 Pt 1):1745–1752. doi: 10.1083/jcb.109.4.1745. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Cartaud A., Ludosky M. A., Courvalin J. C., Cartaud J. A protein antigenically related to nuclear lamin B mediates the association of intermediate filaments with desmosomes. J Cell Biol. 1990 Aug;111(2):581–588. doi: 10.1083/jcb.111.2.581. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Djabali K., Portier M. M., Gros F., Blobel G., Georgatos S. D. Network antibodies identify nuclear lamin B as a physiological attachment site for peripherin intermediate filaments. Cell. 1991 Jan 11;64(1):109–121. doi: 10.1016/0092-8674(91)90213-i. [DOI] [PubMed] [Google Scholar]
  10. Dunia I., Pieper F., Manenti S., van de Kemp A., Devilliers G., Benedetti E. L., Bloemendal H. Plasma membrane-cytoskeleton damage in eye lenses of transgenic mice expressing desmin. Eur J Cell Biol. 1990 Oct;53(1):59–74. [PubMed] [Google Scholar]
  11. Eckert B. S., Daley R. A., Parysek L. M. Assembly of keratin onto PtK1 cytoskeletons: evidence for an intermediate filament organizing center. J Cell Biol. 1982 Feb;92(2):575–578. doi: 10.1083/jcb.92.2.575. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. FitzGerald P. G. Age-related changes in a fiber cell-specific extrinsic membrane protein. Curr Eye Res. 1988 Dec;7(12):1255–1262. doi: 10.3109/02713688809033229. [DOI] [PubMed] [Google Scholar]
  13. FitzGerald P. G., Gottlieb W. The Mr 115 kd fiber cell-specific protein is a component of the lens cytoskeleton. Curr Eye Res. 1989 Aug;8(8):801–811. doi: 10.3109/02713688909000870. [DOI] [PubMed] [Google Scholar]
  14. FitzGerald P. G. Methods for the circumvention of problems associated with the study of the ocular lens plasma membrane-cytoskeleton complex. Curr Eye Res. 1990 Nov;9(11):1083–1097. doi: 10.3109/02713689008997582. [DOI] [PubMed] [Google Scholar]
  15. Fowler W. E., Aebi U. Preparation of single molecules and supramolecular complexes for high-resolution metal shadowing. J Ultrastruct Res. 1983 Jun;83(3):319–334. doi: 10.1016/s0022-5320(83)90139-9. [DOI] [PubMed] [Google Scholar]
  16. Georgatos S. D., Blobel G. Lamin B constitutes an intermediate filament attachment site at the nuclear envelope. J Cell Biol. 1987 Jul;105(1):117–125. doi: 10.1083/jcb.105.1.117. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Georgatos S. D., Weaver D. C., Marchesi V. T. Site specificity in vimentin-membrane interactions: intermediate filament subunits associate with the plasma membrane via their head domains. J Cell Biol. 1985 Jun;100(6):1962–1967. doi: 10.1083/jcb.100.6.1962. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Georgatos S. D., Weber K., Geisler N., Blobel G. Binding of two desmin derivatives to the plasma membrane and the nuclear envelope of avian erythrocytes: evidence for a conserved site-specificity in intermediate filament-membrane interactions. Proc Natl Acad Sci U S A. 1987 Oct;84(19):6780–6784. doi: 10.1073/pnas.84.19.6780. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Goldman R., Goldman A., Green K., Jones J., Lieska N., Yang H. Y. Intermediate filaments: possible functions as cytoskeletal connecting links between the nucleus and the cell surface. Ann N Y Acad Sci. 1985;455:1–17. doi: 10.1111/j.1749-6632.1985.tb50400.x. [DOI] [PubMed] [Google Scholar]
  20. Griffiths G., McDowall A., Back R., Dubochet J. On the preparation of cryosections for immunocytochemistry. J Ultrastruct Res. 1984 Oct;89(1):65–78. doi: 10.1016/s0022-5320(84)80024-6. [DOI] [PubMed] [Google Scholar]
  21. Ireland M., Maisel H. A cytoskeletal protein unique to lens fiber cell differentiation. Exp Eye Res. 1984 Jun;38(6):637–645. doi: 10.1016/0014-4835(84)90182-9. [DOI] [PubMed] [Google Scholar]
  22. Katsuma Y., Swierenga S. H., Marceau N., French S. W. Connections of intermediate filaments with the nuclear lamina and the cell periphery. Biol Cell. 1987;59(3):193–203. doi: 10.1111/j.1768-322x.1987.tb00531.x. [DOI] [PubMed] [Google Scholar]
  23. Maisel H., Perry M. M. Electron microscope observations on some structural proteins of the chick lens. Exp Eye Res. 1972 Jul;14(1):7–12. doi: 10.1016/0014-4835(72)90136-4. [DOI] [PubMed] [Google Scholar]
  24. Pruss R. M., Mirsky R., Raff M. C., Thorpe R., Dowding A. J., Anderton B. H. All classes of intermediate filaments share a common antigenic determinant defined by a monoclonal antibody. Cell. 1981 Dec;27(3 Pt 2):419–428. doi: 10.1016/0092-8674(81)90383-4. [DOI] [PubMed] [Google Scholar]
  25. Ramaekers F. C., Dunia I., Dodemont H. J., Benedetti E. L., Bloemendal H. Lenticular intermediate-sized filaments: biosynthesis and interaction with plasma membrane. Proc Natl Acad Sci U S A. 1982 May;79(10):3208–3212. doi: 10.1073/pnas.79.10.3208. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Vikstrom K. L., Borisy G. G., Goldman R. D. Dynamic aspects of intermediate filament networks in BHK-21 cells. Proc Natl Acad Sci U S A. 1989 Jan;86(2):549–553. doi: 10.1073/pnas.86.2.549. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Wang E. Intermediate filament associated proteins. Ann N Y Acad Sci. 1985;455:32–56. doi: 10.1111/j.1749-6632.1985.tb50402.x. [DOI] [PubMed] [Google Scholar]

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