Tonofibril

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 have an important role in holding them together as tonofibrils. This protein is known to interact with intermediate filaments, specifically keratins. It is synthesized as a giant Precursor protein, profilaggrin (>400 kDA in humans). When the filaggrin binds to keratin intermediate filaments, it causes aggregation in macrofibrils.[2]

gollark: (there is no way this can possibly cause problems later)
gollark: I simply do not exercise, except when I do.
gollark: Also eternal youth/relatively good health, but I figure you would basically have to have that for immortality anyway.
gollark: That's higher than average life expectancy basically everywhere, and for much of it you are an old person and unable to do much.
gollark: I mean "immortality" as in "will not randomly die of old age and such", not "live for an infinite amount of time", which would have problems.

References
  1. "tonofibril" at Dorland's Medical Dictionary
  2. 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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