From the Research
Collagen mRNA is first translated to preprocollagen in the rough endoplasmic reticulum (RER) of fibroblasts and other collagen-producing cells. This process begins when ribosomes attach to the RER membrane and translate the collagen mRNA into the preprocollagen polypeptide chain 1. Preprocollagen is the initial translation product that contains additional peptide sequences at both the N-terminal and C-terminal ends, called propeptides, as well as a signal peptide that directs the growing polypeptide into the RER lumen.
Key Steps in the Process
- The signal peptide is cleaved off, and the molecule undergoes several post-translational modifications including hydroxylation of proline and lysine residues and glycosylation 2.
- These modifications are essential for proper folding and stability of the collagen triple helix.
- After these initial modifications, the molecule is referred to as procollagen, which is then transported to the Golgi apparatus for further processing before secretion outside the cell where it becomes mature collagen.
Regulation of Collagen Production
- The production of collagen is regulated by post-transcriptional mechanisms, including feedback control between secretion and translation rates 3.
- LARP6 and nonmuscle myosin play a role in partitioning collagen mRNAs to the ER membrane, allowing for coordinated initiation of translation on the membrane-bound collagen α1(I) and α2(I) mRNAs 1.
- The regulation of collagen production is critical for maintaining tissue homeostasis and preventing diseases such as fibrosis and Ehlers-Danlos syndrome.