TY - JOUR
T1 - The E3 ubiquitin ligase SMURF2 stabilizes RNA editase ADAR1p110 and promotes its adenosine-to-inosine (A-to-I) editing function
AU - Koganti, Praveen
AU - Kadali, Venkata Narasimha
AU - Manikoth Ayyathan, Dhanoop
AU - Emanuelli, Andrea
AU - Paolini, Biagio
AU - Levy-Cohen, Gal
AU - Blank, Michael
N1 - Publisher Copyright: © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
PY - 2022/4/11
Y1 - 2022/4/11
N2 - Epitranscriptomic changes in RNA catalyzed by the RNA-editing enzyme ADAR1 play an essential role in the regulation of diverse molecular and cellular processes, both under physiological conditions and in disease states, including cancer. Yet, despite a growing body of evidence pointing to ADAR1 as a potential therapeutic target, the mechanisms regulating its cellular abundance and activity, particularly of its constitutively expressed and ubiquitous form, ADAR1p110, are poorly understood. Here, we report the HECT-type E3 ubiquitin ligase SMURF2 as a pivotal regulator of ADAR1p110. We show that SMURF2, which is primarily known to promote the ubiquitin-mediated degradation of its protein substrates, protects ADAR1p110 from proteolysis and promotes its A-to-I editase activity in human and mouse cells and tissues. ADAR1p110’s interactome analysis performed in human cells also showed a positive influence of SMURF2 on the stability and function of ADAR1p110. Mechanistically, we found that SMURF2 directly binds, ubiquitinates and stabilizes ADAR1p110 in an E3 ubiquitin ligase-dependent manner, through ADAR1p110 ubiquitination at lysine-744 (K744). Mutation of this residue to arginine (K744R), which is also associated with several human disorders, including dyschromatosis symmetrica hereditaria (DSH) and some types of cancer, abolished SMURF2-mediated protection of ADAR1p110 from both proteasomal and lysosomal degradation and inactivated ADAR1p110-mediated RNA editing. Our findings reveal a novel mechanism underlying the regulation of ADAR1 in mammalian cells and suggest SMURF2 as a key cellular factor influencing the protein abundance, interactions and functions of ADAR1p110.
AB - Epitranscriptomic changes in RNA catalyzed by the RNA-editing enzyme ADAR1 play an essential role in the regulation of diverse molecular and cellular processes, both under physiological conditions and in disease states, including cancer. Yet, despite a growing body of evidence pointing to ADAR1 as a potential therapeutic target, the mechanisms regulating its cellular abundance and activity, particularly of its constitutively expressed and ubiquitous form, ADAR1p110, are poorly understood. Here, we report the HECT-type E3 ubiquitin ligase SMURF2 as a pivotal regulator of ADAR1p110. We show that SMURF2, which is primarily known to promote the ubiquitin-mediated degradation of its protein substrates, protects ADAR1p110 from proteolysis and promotes its A-to-I editase activity in human and mouse cells and tissues. ADAR1p110’s interactome analysis performed in human cells also showed a positive influence of SMURF2 on the stability and function of ADAR1p110. Mechanistically, we found that SMURF2 directly binds, ubiquitinates and stabilizes ADAR1p110 in an E3 ubiquitin ligase-dependent manner, through ADAR1p110 ubiquitination at lysine-744 (K744). Mutation of this residue to arginine (K744R), which is also associated with several human disorders, including dyschromatosis symmetrica hereditaria (DSH) and some types of cancer, abolished SMURF2-mediated protection of ADAR1p110 from both proteasomal and lysosomal degradation and inactivated ADAR1p110-mediated RNA editing. Our findings reveal a novel mechanism underlying the regulation of ADAR1 in mammalian cells and suggest SMURF2 as a key cellular factor influencing the protein abundance, interactions and functions of ADAR1p110.
KW - A-to-I RNA editing
KW - ADAR1p110
KW - Interactome
KW - SMURF2
KW - Ubiquitination
UR - http://www.scopus.com/inward/record.url?scp=85127925934&partnerID=8YFLogxK
U2 - https://doi.org/10.1007/s00018-022-04272-8
DO - https://doi.org/10.1007/s00018-022-04272-8
M3 - مقالة
C2 - 35403872
SN - 1420-682X
VL - 79
JO - Cellular and Molecular Life Sciences
JF - Cellular and Molecular Life Sciences
IS - 5
M1 - 237
ER -