Table 1.
The enzymes involved in the crucial stages of collagen formation.
| Intracellular Stage of Collagen Formation |
Enzyme | Gene | miRNA | References | |
|---|---|---|---|---|---|
| 1. | COL1A1 gene expression | − | COL1A1 | miR-625-5p, miR-92a-1-5p, miR-129-5p, miR-133b, miR-133a-3p, miR-196b-5p, miR-196a, miR-98, miR-29a, miR-513b-5p |
[12,13,15,16,17,18,23,24,25,26,27,28,29] |
| 2. | Hydroxylation of proline residues | Prolyl,4- hydroxylase |
P4HA1, P4HA2, P4HA3, P4HB |
miR-124-3p, miR-122, miR-30e, − miR-210 |
[30,31,32] [33,34] |
| 3. | Hydroxylation of lysine residues | Lysyl hydroxylase |
PLOD1, PLOD2, PLOD3 |
miR-34c, miR-124, miR-26, miR-663a |
[35,36,37,38] |
| 4. | Glycosylation of some hydroxylysine residues | Glycosyltransferase |
GLT25D1
GLT25D2 |
− | [39,40,41] |
| 5. | Formation of intra-chain and inter-chain disulphide bonds in terminal peptides | Protein disulphide isomerase | P4HB | miR-210 | [33,34] |
| 6. | Procollagen triple helix formation | Hsp-47 protein | SERPINH1 | miR-29b, miR-29a |
[42,43,44] |
| Extracellular stage of collagen formation | Enzyme | Gene | miRNA | Sources | |
| 7. | Cleavage of amino propeptides | Specific N-propeptidases | ADAM2,3 and 14 | miR-29b | [45] |
| 8. | Cleavage of carboxy propeptides | Specific C- propeptidase | BMP1 | miR-194, miR-29c, miR-29b |
[45,46,47] |
| 9. | Aggregation of collagen fibres | Self-assembly | − | − | [48] |
| 10. | Crosslinking Oxidative deamination of epsilon-amino groups of lysyl and hydroxylysine residues located in telopeptide domains to aldehydes |
Lysyl oxidase | LOX | miR-27, miR29b, miR29a, miR-30a, miR-30b, miR-30b-2-3p, miR-142-3p |
[43,49,50,51,52,53,54,55] |