Tonofibril
Tonofibrils are cytoplasmic protein structures in epithelial tissues that converge at desmosomes and hemidesmosomes.[1] They consist of bundles of keratin intermediate filaments (tonofilaments) in epithelial cells that are anchored to the cytoskeleton.[2][3] They were discovered by Rudolf Heidenhain, and first described in detail by Louis-Antoine Ranvier in 1897.[4]
Composition
[edit]Tonofilaments are keratin intermediate filaments that make up tonofibrils in the epithelial tissue. They may also just be referred to as keratin intermediate filaments.[5] In epithelial cells, tonofilaments loop through desmosomes. Electron microscopy has advanced now to illustrate the tonofilaments more clearly.[1]
The protein filaggrin is believed to be synthesized as a giant precursor protein, profilaggrin (>400 kDA in humans). When filaggrin binds to keratin intermediate filaments, the keratin aggregates into macrofibrils.[3]
References
[edit]- ^ a b "tonofibril" at Dorland's Medical Dictionary[dead link]
- ^ "Keratinocytes". Kenhub. Retrieved 30 November 2025.
- ^ a b Sandilands, Aileen; Sutherland, Calum; Irvine, Alan D.; McLean, W. H. Irwin (2009-05-01). "Filaggrin in the frontline: role in skin barrier function and disease". J Cell Sci. 122 (9): 1285–1294. doi:10.1242/jcs.033969. ISSN 0021-9533. PMC 2721001. PMID 19386895.
- ^ Charles, Arwyn; Smiddy, F. G. (1957-09-01). "The Tonofibrils of the Human Epidermis1". Journal of Investigative Dermatology. 29 (5): 327–338. doi:10.1038/jid.1957.108. ISSN 0022-202X. PMID 13502588.
- ^ Windoffer, R; Beil, M; Magin, TM; Leube, RE (5 September 2011). "Cytoskeleton in motion: the dynamics of keratin intermediate filaments in epithelia". The Journal of cell biology. 194 (5): 669–78. doi:10.1083/jcb.201008095. PMID 21893596.
External links
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