{Reference Type}: Journal Article
{Title}: Pseudophosphorylation of single residues of the J-domain of DNAJA2 regulates the holding/folding balance of the Hsc70 system.
{Author}: Velasco-Carneros L;Bernardo-Seisdedos G;Maréchal JD;Millet O;Moro F;Muga A;
{Journal}: Protein Sci
{Volume}: 33
{Issue}: 8
{Year}: 2024 Aug
{Factor}: 6.993
{DOI}: 10.1002/pro.5105
{Abstract}: The Hsp70 system is essential for maintaining protein homeostasis and comprises a central Hsp70 and two accessory proteins that belong to the J-domain protein (JDP) and nucleotide exchange factor families. Posttranslational modifications offer a means to tune the activity of the system. We explore how phosphorylation of specific residues of the J-domain of DNAJA2, a class A JDP, regulates Hsc70 activity using biochemical and structural approaches. Among these residues, we find that pseudophosphorylation of Y10 and S51 enhances the holding/folding balance of the Hsp70 system, reducing cochaperone collaboration with Hsc70 while maintaining the holding capacity. Truly phosphorylated J domains corroborate phosphomimetic variant effects. Notably, distinct mechanisms underlie functional impacts of these DNAJA2 variants. Pseudophosphorylation of Y10 induces partial disordering of the J domain, whereas the S51E substitution weakens essential DNAJA2-Hsc70 interactions without a large structural reorganization of the protein. S51 phosphorylation might be class-specific, as all cytosolic class A human JDPs harbor a phosphorylatable residue at this position.