Regulation of alternative splicing of tau exon 10 by 9G8 and Dyrk1A

• Published in: Neurobiology of aging Vol. 33; no. 7; pp. 1389 - 1399
• Main Authors: Ding, Shaohong, Shi, Jianhua, Qian, Wei, Iqbal, Khalid, Grundke-Iqbal, Inge, Gong, Cheng-Xin, Liu, Fei
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.07.2012
• Subjects: 9G8; Aging; Alternative splicing; Alternative Splicing - physiology; Amino Acid Sequence; Animals; Brain; Chlorocebus aethiops; COS Cells; Cytoplasm; Dementia disorders; Dyrk Kinases; Dyrk1A; Exons; Exons - genetics; HEK293 Cells; Humans; Internal Medicine; Molecular modelling; Molecular Sequence Data; Nervous system; Neurodegeneration; Neurology; Nuclear Proteins - biosynthesis; Nuclear Proteins - genetics; Nuclear transport; Protein Serine-Threonine Kinases - biosynthesis; Protein Serine-Threonine Kinases - genetics; Protein-Tyrosine Kinases - biosynthesis; Protein-Tyrosine Kinases - genetics; Rats; RNA-Binding Proteins - biosynthesis; RNA-Binding Proteins - genetics; Serine; Serine-Arginine Splicing Factors; splicing factors; Tau; Tau protein; tau Proteins - genetics; tau Proteins - metabolism; Tyrosine; Alternative splicing; Tau; 9G8; Neurodegeneration; Dyrk1A
• ISSN: 0197-4580; 1558-1497
• DOI: 10.1016/j.neurobiolaging.2010.11.021

Abstract Adult human brain expresses 6 isoforms of tau protein as a result of alternative splicing. Alternative splicing of exon 10 (E10) leads to tau isoforms containing either 3 (3R-tau) or 4 (4R-tau) microtubule-binding repeats. Imbalance in the 3R-tau/4R-tau ratio causes neurofibrillary degeneration and dementia. Here, we demonstrated that the dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A) interacted with the splicing factor 9G8 and phosphorylated it at several serine residues. Dyrk1A itself promoted tau E10 inclusion, whereas 9G8 inhibited E10 inclusion, and these actions were variable depending on the cell types. Coexpression of Dyrk1A and 9G8 led to their translocation from the nucleus to the cytoplasm and suppressed their ability to regulate tau exon 10 splicing. This action is probably due to their interaction-induced translocation from the nucleus, where the regulation of tau E10 splicing occurs, to the cytoplasm. These findings provide novel insights into the molecular mechanism of the regulation of tau E10 splicing and further our understanding of the neurodegeneration caused by dysregulation of tau E10 splicing.