GSK3beta-Mediated Drp1 Phosphorylation Induced Elongated Mitochondrial Morphology against Oxidative Stress

Chou, Chia‐Hua; Lin, Ching‐Chih; Yang, Ming‐Chang; Wei, Chih‐Chang; Liao, Huei-De; Lin, Run-Chin; Tu, Wen‐Yu; Kao, Tsung-Chieh; Hsu, Chen-Pin; Cheng, Jiin‐Tsuey; Chou, An‐Kuo; Lee, Chu-I; Loh, Joon‐Khim; Howng, Shen-Long; Hong, Yi‐Ren

doi:10.1371/journal.pone.0049112

Cited by 110 publications

(103 citation statements)

References 41 publications

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“…Next, we tested other 2 Drp1 forms with described phosphorylatable residues mutated, Drp1-S579A (corresponding to human Drp1-Ser616; 23 ) and Drp1-S693A 24 and no protection against excitotoxicity-mediated mitochondrial fragmentation was observed (not shown). To test the possibility that ROCK phosphorylated Drp1 in a new, undescribed residue, we immunoprecipitated with a phosphor-Ser antibody followed by western blot with anti Drp1, but no changes were detected after the NMDA treatment (not shown).…”

Section: Resultsmentioning

confidence: 99%

Mitochondrial fragmentation in excitotoxicity requires ROCK activation

et al. 2015

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Section: Resultsmentioning

confidence: 99%

Mitochondrial fragmentation in excitotoxicity requires ROCK activation

et al. 2015

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“…However, NIRKO mice exhibit no changes in phosphorylation of Drp1 at serine residue 616, which stimulates mitochondrial fission, or serine residue 637, which inhibits fission. Recent work has shown that Drp1 can also be phosphorylated at Ser-693 by GSK3-beta (49), and GSK3-beta is a known downstream target of insulin receptor signaling, such that insulin induced phosphorylation of the enzyme reduces its activity. We have previously shown that NIRKO mice display increased GSK3-beta activity (17), but whether this affects Ser-693 phosphorylation of Drp1 and mitochondrial dynamics is unclear, because no antibodies specific to this site exist.…”

Section: Discussionmentioning

confidence: 99%

Insulin resistance in brain alters dopamine turnover and causes behavioral disorders

Kleinridders

Cai

Cappellucci³

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

363

249

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Diabetes and insulin resistance are associated with altered brain imaging, depression, and increased rates of age-related cognitive impairment. Here we demonstrate that mice with a brain-specific knockout of the insulin receptor (NIRKO mice) exhibit brain mitochondrial dysfunction with reduced mitochondrial oxidative activity, increased levels of reactive oxygen species, and increased levels of lipid and protein oxidation in the striatum and nucleus accumbens. NIRKO mice also exhibit increased levels of monoamine oxidase A and B (MAO A and B) leading to increased dopamine turnover in these areas. Studies in cultured neurons and glia cells indicate that these changes in MAO A and B are a direct consequence of loss of insulin signaling. As a result, NIRKO mice develop age-related anxiety and depressive-like behaviors that can be reversed by treatment with MAO inhibitors, as well as the tricyclic antidepressant imipramine, which inhibits MAO activity and reduces oxidative stress. Thus, insulin resistance in brain induces mitochondrial and dopaminergic dysfunction leading to anxiety and depressive-like behaviors, demonstrating a potential molecular link between central insulin resistance and behavioral disorders. A s life expectancy in humans has increased, we are faced with a worldwide epidemic of age-related diseases such as type 2 diabetes (T2D) and Alzheimer's disease (1). These parallel epidemics may not be coincidental. Indeed, studies have demonstrated an association between diabetes and a variety of brain alterations including depression, age-related cognitive decline, Alzheimer's disease, and Parkinson's disease (2, 3). In addition, individuals with both type 1 and type 2 diabetes have been shown to have a variety of abnormalities in brain imaging, including altered brain activity and connectivity by functional MRI (4, 5), altered microstructure by diffusion tensor imaging (6, 7), and altered neuronal circuitry in the striatum (8). Conversely, patients with Alzheimer's disease show signs of central insulin resistance with increased insulin receptor substrate (IRS) 1 serine phosphorylation in the brain and decreased insulin concentrations in the cerebrospinal fluid (9, 10). Furthermore, pilot clinical trials of intranasal insulin administered to individuals with Alzheimer's disease suggest decreased rates of cognitive decline (11).These observations in humans have been mechanistically supported by studies in rodents and cultured cells, which have shown that insulin receptor signaling in brain has an important role in central regulation of metabolism and may also be crucial for proper brain function (12)(13)(14). We have previously demonstrated that mice with insulin resistance in brain due to targeted deletion of the insulin receptor (NIRKO mice) develop hyperphagia, mild obesity, reduced fertility, and decreased counterregulatory response to hypoglycemia (15, 16). NIRKO mice also display glycogen synthase kinase 3 beta (GSK3-beta) activation, resulting in hyperphosphorylation of tau protein, a hallmark of e...

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“…Our previous work demonstrated that GSK3β also binds to Drp1 and is involved in regulating mitochondrial morphology [7]. Drp1 is one of the dynamin-related proteins, a large protein with an amino-terminal GTPase domain, middle domain, insert B, and GTPase effector domain (GED) [8].…”

Section: Introductionmentioning

confidence: 99%

“…Phosphorylation is an important regulator of Drp 1 activity. Interestingly, phosphorylation of Drp 1 at multiple serine residues has opposing functional and morphological effects [7,[10][11][12][13][14][15][16][17][18]. Drp1 S637 was first identified as a phosphorylation site for PKA and as a dephosphorylation site for calcineurin [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have indicated that phosphorylation at Drp1 S637 has beneficial effects in starvation conditions, where mitochondrial are observed to be elongated [19,20] and unite to survive [21] by protecting mitochondria from autophagosomal degradation, permitting mitochondria to maximize energy production and supplying autophagosomal membranes [22]. In addition, GSK3β-mediated phosphorylation of Drp1 S693 is important in controlling mitochondrial morphology under oxidative stress [7]. However, the physiological role of such phosphorylation events remains unclear.…”

Section: Introductionmentioning

confidence: 99%

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

Loh

Lin

Yang

et al. 2015

Biochimica et Biophysica Acta (BBA) - Molecular Cell Research

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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.

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GSK3beta-Mediated Drp1 Phosphorylation Induced Elongated Mitochondrial Morphology against Oxidative Stress

Cited by 110 publications

References 41 publications

Mitochondrial fragmentation in excitotoxicity requires ROCK activation

Mitochondrial fragmentation in excitotoxicity requires ROCK activation

Insulin resistance in brain alters dopamine turnover and causes behavioral disorders

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

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