The prefoldin complex stabilizes the von Hippel-Lindau protein against aggregation and degradation

Abstract

Loss of von Hippel-Lindau protein pVHL function promotes VHL diseases, including sporadic and inherited clear cell Renal Cell Carcinoma (ccRCC). Mechanisms controlling pVHL function and regulation, including folding and stability, remain elusive. Here, we have identified the conserved cochaperone prefoldin complex in a screen for pVHL interactors. The prefoldin complex delivers non-native proteins to the chaperonin T-complex-protein-1-ring (TRiC) or Cytosolic Chaperonin containing TCP-1 (CCT) to assist folding of newly synthesized polypeptides. The pVHL-prefoldin interaction was confirmed in human cells and prefoldin knock-down reduced pVHL expression levels. Furthermore, when pVHL was expressed in Schizosaccharomyces pombe, all prefoldin mutants promoted its aggregation. We mapped the interaction of prefoldin with pVHL at the exon2-exon3 junction encoded region. Low levels of the PFDN3 prefoldin subunit were associated with poor survival in ccRCC patients harboring VHL mutations. Our results link the prefoldin complex with pVHL folding and this may impact VHL diseases progression.

A comprehensive analysis of prefoldins and their implication in cancer

“…Furthermore, PFDN5 was recently found to bind β-actin, and its overexpression promotes the assembly of this monomer into filopodia, thus increasing filopodia density and length, which results in an increase in cell migration as evidenced by transwell experiments ( Fan et al., 2020 ). This folding function is also shared with other proteins, such as for pVHL, since ablation of different prefoldin genes and especially PFDN3 causes aggregation of pVHL ( Chesnel et al., 2020 ). Furthermore, in the nucleus, the classic PFDN complex has been proposed to deliver HDAC1 to the CCT complex for its proper folding, as evidenced by interaction analysis performed in human cells ( Banks et al., 2018 ).…”

“…Unlike archaeal PFDNs, it was not able to prevent citrate synthase aggregation, supporting the idea that eukaryotic PFDN has more specific functions than a regular chaperone as happens in archaea. Nevertheless, eukaryotic PFDN is also able to bind actin and tubulin ( Morita et al, 2018 ), and genetic ablation of the prefoldin genes in yeast alters the microtubules phenotype ( Chesnel et al., 2020 ; Geissler et al., 1998 ).…”

“…As in other organisms, it mediates actin and tubulin folding through their delivery to the CCT chaperonin complex. The importance of the classic PFDN complex in this process is highlighted by the aberrant microtubule assembly in human cell lines after siRNA-mediated downregulation of PFDNs ( Chesnel et al., 2020 ). Furthermore, PFDN5 was recently found to bind β-actin, and its overexpression promotes the assembly of this monomer into filopodia, thus increasing filopodia density and length, which results in an increase in cell migration as evidenced by transwell experiments ( Fan et al., 2020 ).…”

“…Another PFDN that has been especially studied is PFDN3, also known as VBP1, standing for von Hippel-Lindau (VHL) binding protein ( Chesnel et al., 2020 ; Tsuchiya et al., 1996 ). PFDN3 is required for the stability of pVHL, as demonstrated in yeast ( Le Goff et al., 2016 ) and in human cell lines ( Chesnel et al., 2020 ) ( Figure 4 ).…”

“…Another PFDN that has been especially studied is PFDN3, also known as VBP1, standing for von Hippel-Lindau (VHL) binding protein ( Chesnel et al., 2020 ; Tsuchiya et al., 1996 ). PFDN3 is required for the stability of pVHL, as demonstrated in yeast ( Le Goff et al., 2016 ) and in human cell lines ( Chesnel et al., 2020 ) ( Figure 4 ). The PFDN3-mediated stabilization of pVHL enhances the function of the latter on delivering client proteins to the ubiquitin ligase that will send them to proteasomal degradation.…”