GSKIP- and GSK3-mediated anchoring strengthens cAMP/PKA/Drp1 axis signaling in the regulation of mitochondrial elongation.

Autor:	Loh JK; Department of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan; Department of Surgery, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan., Lin CC; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan., Yang MC; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan; Laboratory of Medical Research, Center of Education and Faculty Development, Kaohsiung Armed Forces General Hospital, Kaohsiung, Taiwan., Chou CH; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan., Chen WS; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan., Hong MC; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Kaohsiung, Taiwan., Cho CL; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan., Hsu CM; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan., Cheng JT; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan., Chou AK; Department of Anesthesiology, Kaohsiung Chang Gung Memorial Hospital and College of Medicine, Chang Gung University, Kaohsiung, Taiwan., Chang CH; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Dermatology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan., Tseng CN; Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung, Taiwan., Wang CH; Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan., Lieu AS; Department of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan., Howng SL; Department of Neurosurgery, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan., Hong YR; Department of Biochemistry, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Department of Biological Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan; Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. Electronic address: m835016@cc.kmu.edu.tw.
Jazyk:	angličtina
Zdroj:	Biochimica et biophysica acta [Biochim Biophys Acta] 2015 Aug; Vol. 1853 (8), pp. 1796-807. Date of Electronic Publication: 2015 Apr 25.
DOI:	10.1016/j.bbamcr.2015.04.013
Abstrakt:	GSK3β binding of GSKIP affects neurite outgrowth, but the physiological significance of PKA binding to GSKIP remains to be determined. We hypothesized that GSKIP and GSK3β mediate cAMP/PKA/Drp1 axis signaling and modulate mitochondrial morphology by forming a working complex comprising PKA/GSKIP/GSK3β/Drp1. We demonstrated that GSKIP wild-type overexpression increased phosphorylation of Drp1 S637 by 7-8-fold compared to PKA kinase-inactive mutants (V41/L45) and a GSK3β binding-defective mutant (L130) under H2O2 and forskolin challenge in HEK293 cells, indicating that not only V41/L45, but also L130 may be involved in Drp1-associated protection of GSKIP. Interestingly, silencing either GSKIP or GSK3β but not GSK3α resulted in a dramatic decrease in Drp1 S637 phosphorylation, revealing that both GSKIP and GSK3β are required in this novel PKA/GSKIP/GSK3β/Drp1 complex. Moreover, overexpressed kinase-dead GSK3β-K85R, which retains the capacity to bind GSKIP, but not K85M which shows total loss of GSKIP-binding, has a higher Drp1 S637 phosphorylation similar to the GSKIP wt overexpression group, indicating that GSK3β recruits Drp1 by anchoring rather than in a kinase role. With further overexpression of either V41/L45P or the L130P GSKIP mutant, the elongated mitochondrial phenotype was lost; however, ectopically expressed Drp1 S637D, a phosphomimetic mutant, but not S637A, a non-phosphorylated mutant, restored the elongated mitochondrial morphology, indicating that Drp1 is a downstream effector of direct PKA signaling and possibly has an indirect GSKIP function involved in the cAMP/PKA/Drp1 signaling axis. Collectively, our data revealed that both GSKIP and GSK3β function as anchoring proteins in the cAMP/PKA/Drp1 signaling axis modulating Drp1 phosphorylation. (Copyright © 2015 Elsevier B.V. All rights reserved.)
Databáze:	MEDLINE
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