Heat Shock-induced Phosphorylation of TAR DNA-binding Protein 43 (TDP-43) by MAPK/ERK Kinase Regulates TDP-43 Function.
TAR DNA-binding protein (TDP-43) is a highly conserved and essential DNA- and RNA-binding protein that controls gene expression through RNA processing, in particular, regulation of splicing. Intracellular aggregation of TDP-43 is a hallmark of amyotrophic lateral sclerosis and ubiquitin-positive frontotemporal lobar degeneration. This TDP-43 pathology is also present in other types of neurodegeneration including Alzheimer's disease. We report here that TDP-43 is a substrate of MEK, a central kinase in the MAPK/ERK signaling pathway. TDP-43 dual phosphorylation by MEK, at threonine 153 and tyrosine 155 (p-T153/Y155), was dramatically increased by the heat shock response (HSR) in human cells. HSR promotes cell survival under proteotoxic conditions by maintaining protein homeostasis and preventing protein misfolding. MEK is activated by HSR and contributes to the regulation of proteome stability. Phosphorylated TDP-43 was not associated with TDP-43 aggregation, and p-T153/Y155 remained soluble under conditions that promote protein misfolding. We found that active MEK significantly alters TDP-43-regulated splicing and that phosphomimetic substitutions at these two residues reduce binding to GU-rich RNA. Cellular imaging using a phospho-specific p-T153/Y155 antibody showed that phosphorylated TDP-43 was specifically recruited to the nucleoli, suggesting that p-T153/Y155 regulates a previously unappreciated function of TDP-43 in the processing of nucleolar-associated RNA. These findings highlight a new mechanism that regulates TDP-43 function and homeostasis through phosphorylation and, therefore, may contribute to the development of strategies to prevent TDP-43 aggregation and to uncover previously unexplored roles of TDP-43 in cell metabolism.
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Wen
W
Li
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Ashley N
AN
Reeb
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Binyan
B
Lin
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Praveen
P
Subramanian
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Erin E
EE
Fey
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Catherine R
CR
Knoverek
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and.
Rachel L
RL
French
the Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611.
Eileen H
EH
Bigio
From the Edward Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104 and yayala@slu.edu.
Yuna M
YM
Ayala
D004268:DNA-Binding Proteins / Q000378:metabolism*; D057809:HEK293 Cells / Q000737:chemistry; D006367:HeLa Cells; D018869:Heat-Shock Response; D006801:Humans; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008958:Models, Molecular; D010766:Phosphorylation; D066329:Protein Aggregates; D012262:Ribonucleoside Diphosphate Reductase; D025521:Tumor Suppressor Proteins / Q000378:metabolism
D004268:DNA-Binding Proteins; D066329:Protein Aggregates; C000598624:TARDBP protein, human; D025521:Tumor Suppressor Proteins; C475286:RRM1 protein, human; D012262:Ribonucleoside Diphosphate Reductase; D020930:MAP Kinase Kinase Kinases
MEK kinase; RNA binding protein; RNA-protein interaction; TAR DNA-binding protein 43 (TDP-43) (TARDBP); amyotrophic lateral sclerosis (ALS) (Lou Gehrig disease); heat shock response; neurodegeneration; protein aggregation