Jelena Auch, Anna Carlotta Peddinghaus, Raphael Stoll
The cellular export of large-sized proteins, such as collagen or fibrillin, necessitates a specialized transport pathway tailored towards their size. For collagen and possibly also other bulky proteins, the Transport ANd Golgi Organization 1 (TANGO1) protein plays a substantial role in the transfer from the Endoplasmic Reticulum (ER) to the Golgi apparatus. TANGO1 and related proteins organize the ER exit sites and generate large export structures within the cytosol while anchored to the ER membrane. In contrast to other proteins involved, TANGO1 features a folded domain in the ER lumen, which seems to be central for detecting cargos. This cargo-recognition domain has been shown to bind the collagen-specific chaperone HSP47 (Ishikawa et al. 2016) as well as type IV collagen directly (Arnolds and Stoll 2023). However, the exact molecular mechanism of these interactions remains unknown. The resonance assignments presented here lay the foundation for the experiments studying the binding process on a molecular level and is designed to facilitate investigations into how TANGO1 detects and selects the cargos to be exported.