Cdk5 phosphorylation of huntingtin reduces its cleavage by caspases

Luo, Shouqing; Vacher, Coralie; Davies, J. Eric; Rubinsztein, David C.

doi:10.1083/jcb.200412071

Cited by 168 publications

(158 citation statements)

References 31 publications

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“…Our studies found that phosphorylation at Ser-514 of the androgen receptor, a site distal to the caspase cleavage site at amino acid 154, enhanced cellular toxicity and the production of cytotoxic fragments. Recent work on Htt suggests that CDK5-mediated phosphorylation of Ser-434 reduces cleavage of Htt at a distal caspase-3 cleavage site (amino acid 513) (39). A key role for phosphorylation of Ser-776 of ataxin-1 was shown to trigger toxicity in SCA1 in vivo (40,41).…”

Section: Discussionmentioning

confidence: 99%

Huntingtin Phosphorylation Sites Mapped by Mass Spectrometry

Schilling

Gafni

Torcassi

et al. 2006

Journal of Biological Chemistry

135

114

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Huntingtin (Htt) is a large protein of 3144 amino acids, whose function and regulation have not been well defined. Polyglutamine (polyQ) expansion in the N terminus of Htt causes the neurodegenerative disorder Huntington disease (HD). The cytotoxicity of mutant Htt is modulated by proteolytic cleavage with caspases and calpains generating N-terminal polyQ-containing fragments. We hypothesized that phosphorylation of Htt may modulate cleavage and cytotoxicity. In the present study, we have mapped the major phosphorylation sites of Htt using cell culture models (293T and PC12 cells) expressing fulllength myc-tagged Htt constructs containing 23Q or 148Q repeats. Purified myc-tagged Htt was subjected to mass spectrometric analysis including matrix-assisted laser desorption/ionization mass spectrometry and nano-HPLC tandem mass spectrometry, used in conjunction with on-target alkaline phosphatase and protease digestions. We have identified more than six novel serine phosphorylation sites within Htt, one of which lies in the proteolytic susceptibility domain. Three of the sites have the consensus sequence for ERK1 phosphorylation, and addition of ERK1 inhibitor blocks phosphorylation at those sites. Other observed phosphorylation sites are possibly substrates for CDK5/CDC2 kinases. Mutation of amino acid Ser-536, which is located in the proteolytic susceptibility domain, to aspartic acid, inhibited calpain cleavage and reduced mutant Htt toxicity. The results presented here represent the first detailed mapping of the phosphorylation sites in full-length Htt.

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Section: Discussionmentioning

confidence: 99%

Huntingtin Phosphorylation Sites Mapped by Mass Spectrometry

Schilling

Gafni

Torcassi

et al. 2006

Journal of Biological Chemistry

135

114

View full text Add to dashboard Cite

show abstract

“…Phosphorylation at various serine residues prevents cleavage of mutant huntingtin into more toxic fragments, decreases neural cell death in vitro (5)(6)(7)(8)(9)(10), and/or restores Htt functions that are compromised by the mutation (8,11). The most dramatic effects have been described for huntingtin phosphorylation at serine 13 and serine 16.…”

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confidence: 87%

Ganglioside GM1 induces phosphorylation of mutant huntingtin and restores normal motor behavior in Huntington disease mice

Pardo

Maglione

Alpaugh

et al. 2012

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

151

143

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Huntington disease (HD) is a progressive neurodegenerative monogenic disorder caused by expansion of a polyglutamine stretch in the huntingtin (Htt) protein. Mutant huntingtin triggers neural dysfunction and death, mainly in the corpus striatum and cerebral cortex, resulting in pathognomonic motor symptoms, as well as cognitive and psychiatric decline. Currently, there is no effective treatment for HD. We report that intraventricular infusion of ganglioside GM1 induces phosphorylation of mutant huntingtin at specific serine amino acid residues that attenuate huntingtin toxicity, and restores normal motor function in already symptomatic HD mice. Thus, our studies have identified a potential therapy for HD that targets a posttranslational modification of mutant huntingtin with critical effects on disease pathogenesis.H untington disease (HD) is an inherited neurodegenerative monogenic disorder caused by the expansion of a polyglutamine stretch beyond 36 residues in the amino-terminal domain of huntingtin (Htt), a protein expressed in most tissues and cells. The mutation causes huntingtin to acquire toxic conformation/s and to affect neuronal function and viability. Medium-sized spiny neurons in the corpus striatum are most affected, but neurodegeneration also occurs in the cerebral cortex and, to a minor extent, in other brain areas, resulting in motor and psychiatric symptoms, as well as cognitive decline.The cellular and molecular mechanisms underlying HD pathogenesis are complex. Both loss and gain of function of mutant huntingtin contribute to cause a wide array of neuronal dysfunctions affecting cell signaling, gene transcription, axonal transport, cell and mitochondrial metabolism as well as neurotransmission (1).In recent years, a breakthrough in HD research has been the discovery that posttranslational modifications of mutant Htt are crucial modulators of mutant Htt toxicity (2-4). Phosphorylation at various serine residues prevents cleavage of mutant huntingtin into more toxic fragments, decreases neural cell death in vitro (5-10), and/or restores Htt functions that are compromised by the mutation (8, 11). The most dramatic effects have been described for huntingtin phosphorylation at serine 13 and serine 16. These two amino acid residues are part of the highly conserved amino-terminal "N17" domain of huntingtin, a domain that regulates huntingtin intracellular localization and association to cellular membranes (12, 13), as well as kinetics of mutant huntingtin aggregation (14,15). Phosphomimetic mutations of serine 13 and serine 16 by aspartic or glutamic acid substitution (S13D and S16D or S13E and S16E) decrease the toxicity of mutant huntingtin fragments in vitro (10, 16). In line with these studies, expression of a phosphomimetic (S13D and S16D) mutant form of expanded full-length huntingtin in a BACHD transgenic mouse model was shown to result in a normal phenotype, with no detectable signs of HD pathology by 12 mo (17).These findings suggest that pharmacological interventions that modulate cell sig...

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“…The kinase activity of Cdk5 is required for suppression of mhtt inclusion body formation It was previously reported that Cdk5 physically binds htt (Luo et al, 2005). To examine this molecular interaction, we examined coimmunoprecipitation of mhtt with anti-Cdk5 or anti-p35 antibody, or of Cdk5 or p35 with anti-GFP antibody, but we could not detect binding of either Cdk5 or p35 to any tNhtt-poly(Q)-EGFP proteins under our experimental conditions (data not shown).…”

Section: Suppression Of Mhtt Aggregate Formation By Cdk5/p35mentioning

confidence: 97%

“…We used the N-terminal exon 1 fragment of huntingtin (tNhtt) including the poly(Q) stretch in the middle, which is much shorter than those used previously by Luo et al (2005) and Anne et al (2007). The effect of Cdk5/p35 on tNhtt aggregate formation was examined by transient expression in COS-7 cells, frequently used for studies on mhtt aggregation (Onodera et al, 1997;Hazeki et al, 1999).…”

Section: Suppression Of Mhtt Aggregate Formation By Cdk5/p35mentioning

confidence: 99%

“…Although Cdk5 plays an important physiological role in neuronal development and synaptic activity (Dhavan and Tsai, 2001;Cheung and Ip, 2007), its deregulation by calpain-mediated cleavage of p35 to p25 is implicated in neuronal cell death of several neurodegenerative diseases such as Alzheimer's and Parkinson's disease (Dhavan and Tsai, 2001;Hisanaga and Saito, 2003;Shelton and Johnson, 2004). It is recently reported that Cdk5 phosphorylates htt at Ser434 to reduce N-terminal cleavage, resulting in decreased aggregation (Luo et al, 2005), and at Ser1181 and Ser1201 to prevent the gain of toxic activity (Anne et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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