In: Biology
outline the key cellular steps involved in the production of human type 1 collagen
The steps involved in production of type1 collagen takes place intracellular and extracellular matrix.
1. Intracellular process takes place in nucleus
Transcription: one molecule of Collagen DNA is transcribed to mRNA where two pro-a1 and pro-a2 chains are formed.
Translation
mRNA chains transports into the cytoplasm. Then, with the presence of ribosome translation of proteins begin.
The pre-pro-polypeptide chain travels to the endoplasmic reticulum for futher processing known as post-translational modification.
Post-translational modification
The above chain in endoplasmic reticulum where three main modifications are prepared to become a pro-collagen.
· The removal of signal peptide from the N-terminal
· The hydroxyl groups added to lysine and proline catalysed by hydroxylase enzymes and a cofactor vitamin C. (hydroxylation)
· Glycosylation of lysine with galactose and glucose at the hydroxyl group.
These 3 pro-alpha-chains then gather by winding into a triple helix by zipper-like folding, forms a right-handed coil.
Finally, the pro-collagen molecule moves to the Golgi apparatus for finishing modifications. Then assemble in secretory vesicles to enter the extracellular matrix.
2. Extracellular matrix
Cleavage of propeptides
collagen peptidases perform propeptide cleavage the ends of the procollagen molecule are removed and the molecule converts to tropocollagen.
Collagen Fibril self-Assembly
Then the enzyme Lysyl oxidase acts on lysine and hydroxylysines, and covalent bond b/w tropocollagen molecules produce a collagen. Type I collagen is the most abundant collagen among others.