Many Proteins require the aid of molecular chaperones to achieve a stable folding state and avoid misfolding pathologies. A major eukaryotic chaperone is the cytosolic chaperonin CCT. While CCT is known to fold a significant portion of all cytosolic proteins, there is no general model for the mechanism CCT uses to fold substrate proteins. One class of proteins that CCT is known to fold are β-propeller containing proteins. Here, we present structural and biochemical data on the processes that CCT uses to fold three distinct β-propeller proteins: the G-protein Beta 5 (Gβ5) subunit of the Gβ5-RGS complex, mLST8 of the mTOR complexes, and BBS2, 7, and 9 of the BBSome. We also explore the mechanisms by which these proteins are assembled into their respective signaling complexes after being folded by CCT. We found that each CCT substrate follows a unique folding trajectory and posit that the major determinants underlying each trajectory are governed by interactions between the substrate and CCT and interactions with downstream binding partners.
College and Department
Physical and Mathematical Sciences; Chemistry and Biochemistry
BYU ScholarsArchive Citation
Ludlam, William Grant, "The Role of the Cytosolic Chaperonin CCT in Folding β-Propeller Proteins" (2021). Theses and Dissertations. 9543.
chaperones, CCT, G proteins, mTOR, BBSome, β-propeller, cryo-electron microscopy