TMED10 mediates the trafficking of insulin-like growth factor 2 along the secretory pathway for myoblast differentiation.

Tiantian Li, Feng Yang, Youshan Heng, Shaopu Zhou, Gang Wang, Jianying Wang, Jinhui Wang, Xianwei Chen, Zhong-Ping Yao, Zhenguo Wu, Yusong Guo

Proceedings of the National Academy of Sciences of the United States of America 2023 Nov 14

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The insulin-like growth factor 2 (IGF2) plays critical roles in cell proliferation, migration, differentiation, and survival. Despite its importance, the molecular mechanisms mediating the trafficking of IGF2 along the secretory pathway remain unclear. Here, we utilized a Retention Using Selective Hook system to analyze molecular mechanisms that regulate the secretion of IGF2. We found that a type I transmembrane protein, TMED10, is essential for the secretion of IGF2 and for differentiation of mouse myoblast C2C12 cells. Further analyses indicate that the residues 112-140 in IGF2 are important for the secretion of IGF2 and these residues directly interact with the GOLD domain of TMED10. We then reconstituted the release of IGF2 into COPII vesicles. This assay suggests that TMED10 mediates the packaging of IGF2 into COPII vesicles to be efficiently delivered to the Golgi. Moreover, TMED10 also mediates ER export of TGN-localized cargo receptor, sortilin, which subsequently mediates TGN export of IGF2. These analyses indicate that TMED10 is critical for IGF2 secretion by directly regulating ER export and indirectly regulating TGN export of IGF2, providing insights into trafficking of IGF2 for myoblast differentiation.

Citation

Tiantian Li, Feng Yang, Youshan Heng, Shaopu Zhou, Gang Wang, Jianying Wang, Jinhui Wang, Xianwei Chen, Zhong-Ping Yao, Zhenguo Wu, Yusong Guo. TMED10 mediates the trafficking of insulin-like growth factor 2 along the secretory pathway for myoblast differentiation. Proceedings of the National Academy of Sciences of the United States of America. 2023 Nov 14;120(46):e2215285120