TY - JOUR
T1 - CK2 and GSK3 phosphorylation on S29 controls wild-type ATXN3 nuclear uptake
AU - Pastori, V.
AU - Sangalli, E.
AU - Coccetti, P.
AU - Pozzi, C.
AU - Nonnis, S.
AU - Tedeschi, G.
AU - Fusi, P.
PY - 2010/7
Y1 - 2010/7
N2 - In the present work we show that murine ATXN3 (ATXN3Q6) nuclear uptake is promoted by phosphorylation on serine 29, a highly conserved residue inside the Josephin domain. Both casein kinase 2 (CK2) and glycogen synthase kinase 3 (GSK3) are able to carry out phosphorylation on this residue. S29 phosphorylation was initially assessed in vitro on purified ATXN3Q6, and subsequently confirmed in transfected COS-7 cells, by MS analysis. Site-directed mutagenesis of S29 to an alanine was shown to strongly reduce nuclear uptake, in COS-7 transiently transfected cells overexpressing ATXN3Q6, while substitution with phospho-mimic aspartic acid restored the wild-type phenotype. Finally, treatment with CK2 and GSK3 inhibitors prevented S29 phosphorylation and strongly inhibited nuclear uptake, showing that both kinases are involved in ATXN3Q6 subcellular sorting. Although other authors have previously addressed this issue, we show for the first time that ATXN3 is phosphorylated inside the Josephin domain and that S29 phosphorylation is involved in nuclear uptake of ATXN3.
AB - In the present work we show that murine ATXN3 (ATXN3Q6) nuclear uptake is promoted by phosphorylation on serine 29, a highly conserved residue inside the Josephin domain. Both casein kinase 2 (CK2) and glycogen synthase kinase 3 (GSK3) are able to carry out phosphorylation on this residue. S29 phosphorylation was initially assessed in vitro on purified ATXN3Q6, and subsequently confirmed in transfected COS-7 cells, by MS analysis. Site-directed mutagenesis of S29 to an alanine was shown to strongly reduce nuclear uptake, in COS-7 transiently transfected cells overexpressing ATXN3Q6, while substitution with phospho-mimic aspartic acid restored the wild-type phenotype. Finally, treatment with CK2 and GSK3 inhibitors prevented S29 phosphorylation and strongly inhibited nuclear uptake, showing that both kinases are involved in ATXN3Q6 subcellular sorting. Although other authors have previously addressed this issue, we show for the first time that ATXN3 is phosphorylated inside the Josephin domain and that S29 phosphorylation is involved in nuclear uptake of ATXN3.
KW - ATXN3
KW - CK2
KW - GSK3
KW - Mass spectrometry
KW - Phosphorylation
KW - Subcellular localization
UR - http://www.scopus.com/inward/record.url?scp=77953794834&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=77953794834&partnerID=8YFLogxK
U2 - 10.1016/j.bbadis.2010.03.007
DO - 10.1016/j.bbadis.2010.03.007
M3 - Article
C2 - 20347968
AN - SCOPUS:77953794834
VL - 1802
SP - 583
EP - 592
JO - Biochimica et Biophysica Acta - Molecular Basis of Disease
JF - Biochimica et Biophysica Acta - Molecular Basis of Disease
SN - 0925-4439
IS - 7-8
ER -