Scharaw Sandra, Iskar Murat, Ori Alessandro, Boncompain Gaelle, Laketa Vibor, Poser Ina, Lundberg Emma, Perez Franck, Beck Martin, Bork Peer, Pepperkok Rainer
Cell Biology and Biophysics Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany.
J Cell Biol. 2016 Nov 21;215(4):543-558. doi: 10.1083/jcb.201601090. Epub 2016 Nov 8.
Stimulation of cells with epidermal growth factor (EGF) induces internalization and partial degradation of the EGF receptor (EGFR) by the endo-lysosomal pathway. For continuous cell functioning, EGFR plasma membrane levels are maintained by transporting newly synthesized EGFRs to the cell surface. The regulation of this process is largely unknown. In this study, we find that EGF stimulation specifically increases the transport efficiency of newly synthesized EGFRs from the endoplasmic reticulum to the plasma membrane. This coincides with an up-regulation of the inner coat protein complex II (COPII) components SEC23B, SEC24B, and SEC24D, which we show to be specifically required for EGFR transport. Up-regulation of these COPII components requires the transcriptional regulator RNF11, which localizes to early endosomes and appears additionally in the cell nucleus upon continuous EGF stimulation. Collectively, our work identifies a new regulatory mechanism that integrates the degradation and transport of EGFR in order to maintain its physiological levels at the plasma membrane.
用表皮生长因子(EGF)刺激细胞会通过内溶酶体途径诱导EGF受体(EGFR)的内化和部分降解。为了使细胞持续发挥功能,通过将新合成的EGFR转运到细胞表面来维持EGFR质膜水平。这一过程的调控机制在很大程度上尚不清楚。在本研究中,我们发现EGF刺激可特异性提高新合成的EGFR从内质网到质膜的转运效率。这与内被膜蛋白复合物II(COPII)组分SEC23B、SEC24B和SEC24D的上调相吻合,我们证明这些组分是EGFR转运所特需的。这些COPII组分的上调需要转录调节因子RNF11,其定位于早期内体,并且在持续的EGF刺激下会额外出现在细胞核中。总的来说,我们的工作确定了一种新的调节机制,该机制整合了EGFR的降解和转运,以维持其在质膜上的生理水平。