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Tonofibrils are cytoplasmic protein structures in epithelial tissues that converge at desmosomes and hemidesmosomes. [1] They consist of fine fibrils in epithelial cells that are anchored to the cytoskeleton. [2] They were discovered by Rudolf Heidenhain, and first described in detail by Louis-Antoine Ranvier in 1897. [3]

Composition

Tonofilaments are keratin intermediate filaments that makes up tonofibrils in the epithelial tissue. 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. [2]

References

  1. ^ a b "tonofibril" at Dorland's Medical Dictionary
  2. ^ 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.
  3. ^ 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.

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