Collagen VII maintains proteostasis in dermal fibroblasts by scaffolding TANGO1 cargo

Qingqing Cao, Grace Tartaglia, Michael Alexander, Pyung Hung Park, Shiv Poojan, Mehdi Farshchian, Ignacia Fuentes, Mei Chen, John A. McGrath, Francis Palisson, Julio Salas-Alanis, Andrew P. South*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Lack of type VII collagen (C7) disrupts cellular proteostasis yet the mechanism remains undescribed. By studying the relationship between C7 and the extracellular matrix (ECM)-associated proteins thrombospondin-1 (TSP1), type XII collagen (C12) and tissue transglutaminase (TGM2) in primary human dermal fibroblasts from multiple donors with or without the genetic disease recessive dystrophic epidermolysis bullosa (RDEB) (n=31), we demonstrate that secretion of each of these proteins is increased in the presence of C7. In dermal fibroblasts isolated from patients with RDEB, where C7 is absent or defective, association with the COPII outer coat protein SEC31 and ultimately secretion of each of these ECM-associated proteins is reduced and intracellular levels are increased. In RDEB fibroblasts, overall collagen secretion (as determined by the levels of hydroxyproline in the media) is unchanged while traffic from the ER to Golgi of TSP1, C12 and TGM2 occurs in a type I collagen (C1) dependent manner. In normal fibroblasts association of TSP1, C12 and TGM2 with the ER exit site transmembrane protein Transport ANd Golgi Organization-1 (TANGO1) as determined by proximity ligation assays, requires C7. In the absence of wild-type C7, or when ECM-associated proteins are overexpressed, C1 proximity and intracellular levels increase resulting in elevated cellular stress responses and elevated TGFβ signaling. Collectively, these data demonstrate a role for C7 in loading COPII vesicle cargo and provides a mechanism for disrupted proteostasis, elevated cellular stress and increased TGFβ signaling in patients with RDEB. Furthermore, our data point to a threshold of cargo loading that can be exceeded with increased protein levels leading to pathological outcomes in otherwise normal cells.

Original languageEnglish
Pages (from-to)226-244
Number of pages19
JournalMatrix Biology
Publication statusPublished - Aug 2022


  • and TGFβ signaling
  • Collagen VII
  • ER stress
  • recessive dystrophic epidermolysis bullosa
  • TANGO1
  • thrombospondin


Dive into the research topics of 'Collagen VII maintains proteostasis in dermal fibroblasts by scaffolding TANGO1 cargo'. Together they form a unique fingerprint.

Cite this