Secretion of collagens

Stable Identifier
Reaction [omitted]
Homo sapiens
Locations in the PathwayBrowser
SVG |   | PPTX  | SBGN
Click the image above or here to open this reaction in the Pathway Browser
The layout of this reaction may differ from that in the pathway view due to the constraints in pathway layout
Collagen precursors are co-translated into the ER, where post-translational modifications occur that are essential for oligomerization and stabilization, the latter thought to involve Serpin H1 (HSP47). Trimers are exported from the ER and trafficked through the Golgi network before secretion into the extracellular space and organization into higher order structures. The precise route and mechanism of secretion for collagen is unclear (Canty & Kadler 2005). In the conventional protein secretion pathway cargo is collected at ER exits sites and loaded into small membrane vesicles that are generated by a set of highly conserved proteins called the coat protein complex II (COPII) (Jensen & Schekman 2011). However, these small vesicles of 60-90 nm diameter are too small for collagens some of which assemble in the ER into 300-400 nm rod-like structures. Collagen secretion appears to involve a modification of the COPII process involving TANGO1 and cTAGE5 which form a dimer at ER exit sites (Malhotra & Erlmann 2011). TANGO1-null mice die at birth and are defective in the secretion of a number of different collagens (Wilson et al. 2011). Another recent study suggests that ubiquitination of one of the COPII complex proteins, SEC31, is sufficient to allow formation of vesicles that are large enough to hold procollagen (Jin et al. 2012).
Literature References
PubMed ID Title Journal Year
21878990 Protein export at the ER: loading big collagens into COPII carriers

Malhotra, V, Erlmann, P

EMBO J 2011
21967573 Stepwise proteolytic activation of type I procollagen to collagen within the secretory pathway of tendon fibroblasts in situ

Lu, Y, Canty-Laird, EG, Kadler, KE

Biochem J 2012
Orthologous Events
Cite Us!