New insights into the functions and localization of nuclear CCT protein complex in K562 leukemia cells

Purpose: The eukaryotic cytosolic chaperonin containing TCP-1 (CCT) plays an important role in maintaining cellular homeostasis by assisting the folding of many proteins and is also well known for the critical roles in disease. However, the functions of CCT complex have not been established globally, especially when translocating into nuclear. The purpose of this study is to explore the function of CCT in nuclear and present a strategy in clinical proteomics studies.

Experimental design: Blue native polyacrylamide gel electrophoresis (BN-PAGE) combined with mass spectrometry was applied to separate and identify CCT protein complexes.

Results: We isolated the CCT complex in K562 nucleus and identified a novel CCT complex containing 40 protein components involved in protein folding, RNA processing, apoptosis, and cell metabolism. The interactions between four candidate proteins and CCT were confirmed by immunoblotting. Computational biological analyses and independent biochemical assays validated the overall quality of interactions.

Conclusions and clinical relevance: Our results support clues that CCT might play an unexpected role in various biological processes including RNA processing. And we envision future applications for this system searching for new clues of CCT in disease and readily be applied to the clinic.