Difference between Tonofibrils and Tonofilaments


They are protein structures found in the epithelial tissues. They converge at hemidesmosomes and desmosomes. They are composed of thin fibrils that are connected to the cytoskeletal structures. Tonofilaments are keratin intermediate filaments constituting tonofibrils in the epithelial tissue. In other words, they are the noticeable bundles of tonofilaments. Sometimes, a protein called filaggrin binds with keratin intermediate filaments to form macro fibrils.


They are keratin intermediate filaments seen in the epithelial tissues. Tonofilaments are made of keratin proteins, and they bundle to form a tonofibril. They are prominent beneath the desmosomal plaques. They loop through the desmosomes in the epithelial cells. Also, they interact with the intracellular proteins found in the plaques. Additionally, hemidesmosomes too interact with the tonofilaments.

Difference between Tonofibrils and Tonofilaments



They are cytoplasmic structures that converge at hemidesmosomes and desmosomes.

They are keratin intermediate filaments that bundle together and form tonofibrils.

They are thicker than tonofilaments.

They are finer than tonofibrils.

Frequently Asked Questions on Difference between Tonofibrils and Tonofilaments

What are desmosomes?

They are specialised cell structures for adhesion. They are randomly arranged adhesion spots on the plasma membrane. Desmosomes are composed of keratin intermediate filaments and other proteins.

What are intermediate filaments?

They are cytoskeletal structures composed of proteins. Some interact with the hemidesmosomes and desmosomes in the plasma membrane, and help in cell adhesion. They are found in the cells of most invertebrates and vertebrates.

What is the difference between fibres and fibrils?

Fibrils are thin structural units that are usually smaller than fibres. The diameter of a fibril ranges from 10-100 nanometres. Whereas the diameter of fibres is measured on micro to milli scale.

What is filaggrin?

Filaggrin is a special protein that helps in the aggregation of filaments. Usually, it binds to the keratin filaments in epithelial cells. It is vital in regulating epidermal homeostasis.

Also Read: Structure and Function of Cytoskeleton

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