Difference Between Tonofibrils and Tonofilaments - Testbook
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What are Tonofibrils?
Tonofibrils are protein structures primarily found in epithelial tissues. They connect at desmosomes and hemidesmosomes. Composed of thin fibrils, they connect to the cytoskeletal structures. Tonofilaments, which are keratin intermediate filaments, form tonofibrils in epithelial tissues. In simpler terms, tonofibrils are visible clusters of tonofilaments. Occasionally, a protein known as filaggrin binds with keratin intermediate filaments to form macro fibrils.
What are Tonofilaments?
Tonofilaments are keratin intermediate filaments found in epithelial tissues. They are made of keratin proteins and bundle together to form a tonofibril. Tonofilaments are especially noticeable under desmosomal plaques. They pass through the desmosomes in epithelial cells and interact with the intracellular proteins present in the plaques. Moreover, hemidesmosomes also interact with tonofilaments.
Comparing Tonofibrils and Tonofilaments
|
Tonofibrils |
Tonofilaments |
|---|---|
|
These are cytoplasmic structures that connect at desmosomes and hemidesmosomes. |
These are keratin intermediate filaments that bundle up to form tonofibrils. |
|
They are generally thicker than tonofilaments. |
They are finer compared to tonofibrils. |
Further Reading: Structure and Function of Cytoskeleton
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Frequently Asked Questions
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.
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