The C haperonin C ontaining T cp1 (CCT) maintains cellular protein folding homeostasis in
the eukaryotic cytosol by assisting the biogenesis of many proteins, including actins,
tubulins, and regulators of the cell cycle. Here, we demonstrate that the essential and
conserved eukaryotic phosducin-like protein 2 (PhLP2/PLP2) physically interacts with CCT
and modulates its folding activity. Consistent with this functional interaction, temperature-
sensitive alleles of Saccharomyces cerevisiae PLP2 exhibit cytoskeletal and cell cycle …

Phosducin-like proteins (PhLPs) are a conserved family of small thioredoxin-like proteins
that were originally identified as modulators of heterotrimeric G protein signaling in the retina
(Schroder and Lohse, 1996). Subsequently, they were shown to have roles in G protein
signaling in other cell types as well as having G protein-independent functions (Flanary et
al., 2000; Blaauw et al., 2003). One of the other functions of PhLPs is the regulation of the
eukaryotic protein-folding machine known as Chaperonin Containing Tcp1 (CCT; also …