Affiliations: [a] Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu, China
| [b] Department of Biochemistry and Molecular Biology, School of Medicine, Nantong University, Nantong, Jiangsu, China
| [c] Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
Correspondence:
[*]
Correspondence to: Fei Liu, Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State
Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY, USA. Tel.:
+1 7184945263; Fax: +1 7184941080; E-mail: feiliu63@hotmail.com and Jianlan Gu, Key Laboratory of
Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong
University, Nantong, Jiangsu, China. Tel.: +86 51385051813; Fax: +86 51385511585; E-mail: ntgjlan@163.com.
Abstract: Trans-active response DNA-binding protein of 43 kDa (TDP-43) is a highly conserved and ubiquitously expressed nuclear protein. As a member of heterogeneous ribonucleoproteins, TDP-43 plays pivotal roles in mRNA processing. We recently found that TDP-43 promoted tau mRNA instability via acting on the 3’-untranslated region of its mRNA and enhanced tau exon 10 inclusion. TDP-43 is a phospho-protein. The function and the pathological aggregation of TDP-43 are regulated by the phosphorylation. In the present study, we determined phosphorylation of TDP-43 by cyclic AMP-dependent protein kinase (PKA). We found that TDP-43 was co-immunoprecipitated by and co-localized with PKA in the nucleus. PKA phosphorylated TDP-43 at Ser379, Ser403/404, and Ser409/410 in vitro and in cultured cells. Phosphorylation of TDP-43 at these sites enhanced mutually their phosphorylation by PKA in vitro and in cultured cells. Overexpression of PKA suppressed TDP-43’s activity in promoting tau mRNA instability and tau exon 10 inclusion. These findings shed light on the role of PKA in phosphorylation and function of TDP-43. Downregulation of PKA signaling in AD brain may attenuate the impact of TDP-43 pathology in tau pathogenesis.
