TY - JOUR
T1 - Granulins modulate liquid–liquid phase separation and aggregation of the prion-like C-terminal domain of the neurodegeneration-associated protein TDP-43
AU - Bhopatkar, Anukool A.
AU - Uversky, Vladimir N.
AU - Rangachari, Vijayaraghavan
N1 - Funding Information:
This work was supported by NIA, National Institutes of Health Grants 1R56AG062292-01 (to V. R.) and RF1AG055088 (to V. N. U.), NIGMS, National Institutes of Health Grants R01GM120634 and 8 P20 GM-103476–11 (to V. R.), National Science Foundation Grant CBET 1802793 (to V. R.), and National Center for Research Resources, National Institutes of Health Grant 5P20RR01647-11 (to V. R.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.
Funding Information:
This work was supported by NIA, National Institutes of Health Grants 1R56AG062292-01 (to V. R.) and RF1AG055088 (to V. N. U.), NIGMS, National Institutes of Health Grants R01GM120634 and 8 P20 GM-103476 ?11 (to V. R.), National Science Foundation Grant CBET 1802793 (to V. R.), and National Center for Research Resources, National Institutes of Health Grant 5P20RR01647-11 (to V. R.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We thank Dr. Nicholas Fawzi (Brown University) for advice regarding TDP-43 CTD purification. We also thank Dr. Jonathan Lindner at USM for help with fluorescence microscopy.
Publisher Copyright:
© 2020 Bhopatkar et al.
PY - 2020/2/21
Y1 - 2020/2/21
N2 - TAR DNA-binding protein 43 (TDP-43) has emerged as a key player in many neurodegenerative pathologies, including frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Hallmarks of both FTLD and ALS are the toxic cytoplasmic inclusions of the prion-like C-terminal fragments of TDP-43 CTD (TDP-43 C-terminal domain), formed upon proteolytic cleavage of full-length TDP-43 in the nucleus and subsequent transport to the cytoplasm. Both full-length TDP-43 and its CTD are also known to form stress granules by coacervating with RNA in the cytoplasm during stress and may be involved in these pathologies. Furthermore, mutations in the PGRN gene, leading to haploinsufficiency and diminished function of progranulin (PGRN) protein, are strongly linked to FTLD and ALS. Recent reports have indicated that proteolytic processing of PGRN to smaller protein modules called granulins (GRNs) contributes to FTLD and ALS progression, with specific GRNs exacerbating TDP-43–induced cytotoxicity. Here we investigated the interactions between the proteolytic products of both TDP-43 and PGRN. Based on structural disorder and charge distributions, we hypothesized that GRN-3 and GRN-5 could interact with the TDP-43 CTD. We show that, under both reducing and oxidizing conditions, GRN-3 and GRN-5 interact with and differentially modulate TDP-43 CTD aggregation and/or liquid–liquid phase separation in vitro. GRN-3 promoted insoluble aggregates of the TDP-43 CTD while GRN-5 mediated liquid–liquid phase separation. These results constitute the first observation of an interaction between GRNs and TDP-43, suggesting a mechanism by which attenuated PGRN function could lead to familial FTLD or ALS.
AB - TAR DNA-binding protein 43 (TDP-43) has emerged as a key player in many neurodegenerative pathologies, including frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Hallmarks of both FTLD and ALS are the toxic cytoplasmic inclusions of the prion-like C-terminal fragments of TDP-43 CTD (TDP-43 C-terminal domain), formed upon proteolytic cleavage of full-length TDP-43 in the nucleus and subsequent transport to the cytoplasm. Both full-length TDP-43 and its CTD are also known to form stress granules by coacervating with RNA in the cytoplasm during stress and may be involved in these pathologies. Furthermore, mutations in the PGRN gene, leading to haploinsufficiency and diminished function of progranulin (PGRN) protein, are strongly linked to FTLD and ALS. Recent reports have indicated that proteolytic processing of PGRN to smaller protein modules called granulins (GRNs) contributes to FTLD and ALS progression, with specific GRNs exacerbating TDP-43–induced cytotoxicity. Here we investigated the interactions between the proteolytic products of both TDP-43 and PGRN. Based on structural disorder and charge distributions, we hypothesized that GRN-3 and GRN-5 could interact with the TDP-43 CTD. We show that, under both reducing and oxidizing conditions, GRN-3 and GRN-5 interact with and differentially modulate TDP-43 CTD aggregation and/or liquid–liquid phase separation in vitro. GRN-3 promoted insoluble aggregates of the TDP-43 CTD while GRN-5 mediated liquid–liquid phase separation. These results constitute the first observation of an interaction between GRNs and TDP-43, suggesting a mechanism by which attenuated PGRN function could lead to familial FTLD or ALS.
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U2 - 10.1074/jbc.RA119.011501
DO - 10.1074/jbc.RA119.011501
M3 - Article
C2 - 31911437
AN - SCOPUS:85079897517
SN - 0021-9258
VL - 295
SP - 2506
EP - 2519
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 8
ER -