TANGO1 and SEC12 are copackaged with procollagen I to facilitate the generation of large COPII carriers.
Yuan L, Kenny SJ, Hemmati J, Xu K, Schekman R.
Proc Natl Acad Sci U S A. 2018 Dec 26;115(52):E12255-E12264. doi: 10.1073/pnas.1814810115. PMID: 30545919.