UBC9-dependent Association between Calnexin and Protein Tyrosine Phosphatase 1B (PTP1B) at the Endoplasmic Reticulum

作者：Lee Dukgyu; Kraus Allison; Prins Daniel; Groenendyk Jody; Aubry Isabelle; Liu Wen Xin; Li Hao Dong; Julien Olivier; Touret Nicolas; Sykes Brian D; Tremblay Michel L; Michalak Marek^*

来源：JOURNAL OF BIOLOGICAL CHEMISTRY, 2015, 290(9): 5725-5738.

DOI：10.1074/jbc.M114.635474

Calnexin is a type I integral endoplasmic reticulum (ER) membrane protein, molecular chaperone, and a component of the translocon. We discovered a novel interaction between the calnexin cytoplasmic domain and UBC9, a SUMOylation E2 ligase, which modified the calnexin cytoplasmic domain by the addition of SUMO. We demonstrated that calnexin interaction with the SUMOylation machinery modulates an interaction with protein tyrosine phosphatase 1B (PTP1B), an ER-associated protein tyrosine phosphatase involved in the negative regulation of insulin and leptin signaling. We showed that calnexin and PTP1B form UBC9-dependent complexes, revealing a previously unrecognized contribution of calnexin to the retention of PTP1B at the ER membrane. This work shows that the SUMOylation machinery links two ER proteins from divergent pathways to potentially affect cellular protein quality control and energy metabolism.

• 出版日期2015-2-27
• 单位McGill