LRRK2 Facilitates tau Phosphorylation through Strong Interaction with tau and cdk5

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• 作者：Mary R. Shanley ; Dillon Hawley ; Shirley Leung ; Nikhat F. Zaidi ; Roshni Dave ; Kate A. Schlosser ; Rina Bandopadhyay ; Scott A. Gerber ; Min Liu
• 刊名：Biochemistry
• 出版年：2015
• 出版时间：August 25, 2015
• 年：2015
• 卷：54
• 期：33
• 页码：5198-5208
• 全文大小：488K
• ISSN：1520-4995

文摘

Leucine-rich repeat kinase 2 (LRRK2) and tau have been identified as risk factors of Parkinson鈥檚 disease (PD). As LRRK2 is a kinase and tau is hyperphosphorylated in some LRRK2 mutation carriers of PD patients, the obvious hypothesis is that tau could be a substrate of LRRK2. Previous reports that LRRK2 phosphorylates free tau or tubulin-associated tau provide direct support for this proposition. By comparing LRRK2 with cdk5, we show that wild-type LRRK2 and the G2019S mutant phosphorylate free recombinant full-length tau protein with specific activity 480- and 250-fold lower than cdk5, respectively. More strikingly tau binds to wt LRRK2 or the G2019S mutant 140- or 200-fold more strongly than cdk5. The extremely low activity of LRRK2 but strong binding affinity with tau suggests that LRRK2 may facilitate tau phosphorylation as a scaffold protein rather than as a major tau kinase. This hypothesis is further supported by the observation that (i) cdk5 or tau coimmunoprecipitates with endogenous LRRK2 in SH-SY5Y cells, in mouse brain tissue, and in human PBMCs; (ii) knocking down endogenous LRRK2 by its siRNA in SH-SY5Y cells reduces tau phosphorylation at Ser396 and Ser404; (iii) inhibiting LRRK2 kinase activity by its inhibitors has no effect on tau phosphorylation at these two sites; and (iv) overexpressing wt LRRK2, the G2019S mutant, or the D1994A kinase-dead mutant in SH-SY5Y cells has no effect on tau phosphorylation. Our results suggest that LRRK2 facilitates tau phosphorylation indirectly by recruiting tau or cdk5 rather than by directly phosphorylating tau.