Chaperonin-containing TCP-1 complex directly binds to the cytoplasmic domain of the LOX-1 receptor

• Affinity isolation was used to identify proteins that bind LOX-1 cytoplasmic domain.
• CCT complex subunits were found to constitutively bind the LOX-1 cytoplasmic domain.
• LOX-1/CCT binding was verified in cells via immunoprecipitation and immunostaining.
• Purified native CCT could directly bind to the LOX-1 cytoplasmic domain peptide.
• Oxidized low-density lipoprotein suppressed the LOX-1/CCT interaction.

Lectin-like oxidized low-density lipoprotein receptor (LOX-1) is a scavenger receptor that binds oxidized low-density lipoprotein (OxLDL) and has a role in atherosclerosis development. The N-terminus intracellular region (cytoplasmic domain) of LOX-1 mediates receptor internalization and trafficking, potentially through intracellular protein interactions. Using affinity isolation, we identified 6 of the 8 components of the chaperonin-containing TCP-1 (CCT) complex bound to LOX-1 cytoplasmic domain, which we verified by coimmunoprecipitation and immunostaining in human umbilical vein endothelial cells. We found that the interaction between CCT and LOX-1 is direct and ATP-dependent and that OxLDL suppressed this interaction. Understanding the association between LOX-1 and the CCT complex may facilitate the design of novel therapies for cardiovascular disease.

Structured summary of protein interactions:LOX-1physically interacts with CCT1 by pull down (View interaction)LOX-1physically interacts with CCT1 by anti bait coimmunoprecipitation (View interaction)LOX-1, M6PR1 and CCT1colocalize by fluorescence microscopy (View interaction)LOX-1physically interacts with CCT1, CCT3, CCT7, CCT5, CCT4 and CCT6A by pull down (View interaction)CCT1, LOX-1 and EEA1 colocalize by fluorescence microscopy (View interaction)CCT1 and LOX-1 colocalize by fluorescence microscopy (View interaction)LOX-1 physically interacts with CCT4 by anti bait coimmunoprecipitation (View interaction)LOX-1 binds to CCT1 by pull down (View interaction)LOX-1 binds to CCT4 by pull down (View interaction)