Proteolytic processing of TAR DNA binding protein‐43 by caspases produces C‐terminal fragments with disease defining properties independent of progranulin

Dormann, Dorothee; Capell, Anja; Carlson, A. J.; Shankaran, Sunita S.; Rodde, Ramona; Neumann, Manuela; Kremmer, Elisabeth; Matsuwaki, Takashi; Yamanouchi, Keitaro; Nishihara, Masugi; Haass, Christian

doi:10.1111/j.1471-4159.2009.06211.x

Cited by 144 publications

(155 citation statements)

References 56 publications

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“…These results suggest that some of the abnormal TDP-43 fragments in ALS CNS tissue lack the C-terminal end and are generated by calpain cleavage. Consistent with previous reports on cultured human cells treated with staurosporine 20,29 , treatment of HeLa cell lysates with a large amount (ten units) of caspase-3 generated fragments with an apparent molecular mass of 35-kDa (Fig. 6f, open asterisk).…”

Section: Resultssupporting

confidence: 92%

A role for calpain-dependent cleavage of TDP-43 in amyotrophic lateral sclerosis pathology

et al. 2012

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Both mislocalization of TDP-43 and downregulation of RNA-editing enzyme ADAR2 colocalize in the motor neurons of amyotrophic lateral sclerosis patients, but how they are linked is not clear. Here we demonstrate that activation of calpain, a Ca 2 þ -dependent cysteine protease, by upregulation of Ca 2 þ -permeable AMPA receptors generates carboxyterminal-cleaved TDP-43 fragments and causes mislocalization of TDP-43 in the motor neurons expressing glutamine/arginine site-unedited GluA2 of conditional ADAR2 knockout (AR2) mice that mimic the amyotrophic lateral sclerosis pathology. These abnormalities are inhibited in the AR2res mice that express Ca 2 þ -impermeable AMPA receptors in the absence of ADAR2 and in the calpastatin transgenic mice, but are exaggerated in the calpastatin knockout mice. Additional demonstration of calpain-dependent TDP43 fragments in the spinal cord and brain of amyotrophic lateral sclerosis patients, and high vulnerability of amyotrophic lateral sclerosis-linked mutant TDP43 to cleavage by calpain support the crucial role of the calpain-dependent cleavage of TDP43 in the amyotrophic lateral sclerosis pathology.

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Section: Resultssupporting

confidence: 92%

A role for calpain-dependent cleavage of TDP-43 in amyotrophic lateral sclerosis pathology

et al. 2012

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“…3a). In accordance with a previous study 18 , these results suggest the following pathway of TDP-43 turnover: initially, TDP-43 is cleaved, which generates CTFs, and then a proportion of the CTFs become insoluble and finally phosphorylated. Recent reports suggest that the oxidation of Cys173 and Cys175 promotes the aggregation of CTFs [19][20][21] .…”

Section: Resultssupporting

confidence: 78%

The cleavage pattern of TDP-43 determines its rate of clearance and cytotoxicity

et al. 2015

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TAR DNA-binding protein of 43 kDa (TDP-43) and its C-terminal fragment of 25 kDa (CTF25) play critical roles in amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Although the overexpression of TDP-43 in cultured cells and animals results in the production of CTF25, the cleavage site that generates CTF25 and biological significance of the cleavage remain undetermined. Here we identify Asp174 as a cleavage site for CTF25. TDP-43 is cleaved initially after Asp174, which activates caspase-3/7 to accelerate TDP-43 fragmentation. Consequently, blockage of this cleavage results in a severe delay in TDP-43 clearance and prolonged necrotic cell death. We further show that the endoplasmic reticulum membrane-bound caspase-4 is the enzyme responsible for the cleavage after Asp174 and inhibition of caspase-4 activity slows TDP-43 fragmentation and reduces cell viability. These findings suggest that caspase-4-mediated cleavage after Asp174 is an initiator of TDP-43 clearance, which is required to avoid cell death induced by overexpressed TDP-43. A myotrophic lateral sclerosis (ALS) is one of the most devastating neurodegenerative diseases and is characterized by muscle weakness due to the degeneration of both upper and lower motor neurons. Although the pathogenic mechanism of ALS remains unresolved, the RNA-binding protein TDP-43 has been shown to accumulate in cytoplasmic inclusions in the affected regions of the spinal cord and brain in patients with ALS and frontotemporal lobar degeneration (FTLD), respectively 1,2 . Subsequently, mutations linked with ALS and FTLD have been identified in the gene that encodes TDP-43, which has confirmed the significance of TDP-43 in the pathogenesis of these diseases 3,4 . Most of these mutations occur within or near the carboxyl-terminal (C-terminal) glycine-rich domain (GRD) of TDP-43, except for the D169G point mutation that resides in RNA recognition motif 1 (refs 3,4). TDP-43 is normally localized predominantly in the nucleus. However, in ALS and FTLD patients with TDP-43-positive cytoplasmic inclusions, the protein is abnormally phosphorylated, ubiquitinated and truncated. This results in the accumulation of an B25-kDa C-terminal fragment (CTF25), in addition to other minor CTFs and the full-length TDP-43, in cytoplasmic aggregates. CTFs are hallmarks of forms of disease whose pathology is associated exclusively with abnormalities in TDP-43 and are observed in patients with not only ALS and FTLD but also Alzheimer's disease 5 . Amino-terminal (N-terminal) analysis of CTFs obtained from brain autopsies of patients with FTLD has resulted in the identification of three cleavage sites, Arg208, Asp219 and Asp247, which give rise to CTFs 6,7 . However, the expected sizes of the resulting CTFs are less than 25 kDa, which suggests that CTF25 is probably cleaved at a different position.TDP-43 is a widely expressed 414-amino acid (a.a.) protein comprised of two RNA recognition motifs (RRM1 at a.a. 106-176 and RRM2 at a.a. 191-262) and the GRD 8,9 . The chronic stabilization...

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“…8,9 Current understanding suggests that proteolytic processing of TDP-43 is caspase dependent and several caspase-dependent cleavage sites have previously been suggested. 7,10,11 However, a new study has provided strong evidence of calpain-dependent TDP-43 fragments in the spinal cord and brain of ALS patients and a high vulnerability of ALSlinked mutant TDP-43 to cleavage by calpain. 12 Based on these results, TDP-43 is susceptible to be the substrate of both calpain and caspase-3.…”

Section: Introductionmentioning

confidence: 99%

Dual Vulnerability of TDP-43 to Calpain and Caspase-3 Proteolysis after Neurotoxic Conditions and Traumatic Brain Injury

Yang

Lin

Robertson

et al. 2014

J Cereb Blood Flow Metab

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Transactivation response DNA-binding protein 43 (TDP-43) proteinopathy has recently been reported in chronic traumatic encephalopathy, a neurodegenerative condition linked to prior history of traumatic brain injury (TBI). While TDP-43 appears to be vulnerable to proteolytic modifications under neurodegenerative conditions, the mechanism underlying the contribution of TDP-43 to the pathogenesis of TBI remains unknown. In this study, we first mapped out the calpain or caspase-3 TDP-43 fragmentation patterns by in vitro protease digestion. Concurrently, in cultured cerebrocortical neurons subjected to cell death challenges, we identified distinct TDP-43 breakdown products (BDPs) of 35, 33, and 12 kDa that were indicative of dual calpain/caspase attack. Cerebrocortical culture incubated with calpain and caspase-fragmented TDP-43 resulted in neuronal injury. Furthermore, increased TDP-43 BDPs as well as redistributed TDP-43 from the nucleus to the cytoplasm were observed in the mouse cortex in two TBI models: controlled cortical impact injury and overpressure blast-wave-induced brain injury. Finally, TDP-43 and its 35 kDa fragment levels were also elevated in the cerebrospinal fluid (CSF) of severe TBI patients. This is the first evidence that TDP-43 might be involved in acute neuroinjury and TBI pathology, and that TDP-43 and its fragments may have biomarker utilities in TBI patients.

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Proteolytic processing of TAR DNA binding protein‐43 by caspases produces C‐terminal fragments with disease defining properties independent of progranulin

Cited by 144 publications

References 56 publications

A role for calpain-dependent cleavage of TDP-43 in amyotrophic lateral sclerosis pathology

A role for calpain-dependent cleavage of TDP-43 in amyotrophic lateral sclerosis pathology

The cleavage pattern of TDP-43 determines its rate of clearance and cytotoxicity

Dual Vulnerability of TDP-43 to Calpain and Caspase-3 Proteolysis after Neurotoxic Conditions and Traumatic Brain Injury

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