SARS-CoV-2 9b binds TOMM70

Stable Identifier
R-HSA-9709663
Type
Reaction [binding]
Species
Homo sapiens
Related Species
Severe acute respiratory syndrome coronavirus 2
Compartment
mitochondrial outer membrane
ReviewStatus
5/5
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SARS-CoV-2 9b binds TOMM70
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The severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) open reading frame 9b protein (ORF9b or 9b) is an accessory protein which is highly homologous to SARS-CoV-1 9b (Jiang HW et al. 2020; Gordon DE et al. 2020a). Both SARS-CoV-1 and SARS-CoV-2 9b proteins localize to the membrane of mitochondria to suppress host innate immunity (Shi CS et al. 2014; Jiang HW et al. 2020; Gordon DE et al. 2020a). Affinity purification using HEK 293T cells coupled with mass spectrometry (AP-MS) analysis identified direct interaction between the mitochondrial import receptor subunit TOM70 (TOMM70) protein and tagged 9b of SARS-CoV-1 and SARS-CoV-2 (Gordon DE et al. 2020a, b). Further, endogenous TOMM70 co-precipitated with Strep-tagged 9b from SARS-CoV-1 and SARS-CoV-2 expressed in both HEK293T and human lung epithelial A549 cells (Gordon DE et al. 2020a). Immunostaining of tagged SARS-CoV-1 9b and SARS-CoV-2 9b revealed that viral 9b co-localized with TOMM70 upon expression in HEK 293T cells or in a human epithelial cell line derived from cervical cancer (HeLa) (Jiang HW et al. 2020; Gordon DE et al. 2020a). Similar findings were observed in SARS-CoV-2-infected human colorectal adenocarcinoma (Caco-2) cells (Gordon DE et al. 2020a). These findings suggest that viral 9b and TOMM70 form a complex and this interaction is conserved between SARS-CoV-1 and SARS-CoV-2 (Jiang HW et al. 2020; Gordon DE et al. 2020a).

TOMM70 is a member of the TOM complex that transports cytosolic pre-proteins destined for the mitochondrial compartments (reviewed in Sokol AM et al. 2014; Kreimendahl S & Rassow J 2020). The C-terminal tetratricopeptide repeat (TPR) motifs in TOMM70 recognizes the internal mitochondrial targeting signals (MTSs) of mitochondrial protein precursors in the cytosol and mediates their translocation to the mitochondria (reviewed in Sokol AM et al. 2014; Kreimendahl S & Rassow J 2020). The molecular chaperone complexes of heat shock protein 90 kDa (HSP90) and HSP70 bind to the N-terminal TPR clamp domain of TOMM70 and thus facilitate delivery of precursor proteins to TOMM70 (Young JC et al. 2003; Zanphorlin LM et al. 2016). Further, TOMM70 is involved in the activation of antiviral immunity by interacting with the mitochondrial antiviral signaling protein (MAVS) (Liu XY et al. 2010). Association of TOMM70 with MAVS is thought to promote the recruitment and activation of TBK1 and IRF3 to MAVS upon viral infection (Liu XY et al. 2010). Cryo–electron microscopy (cryo-EM) structure of the TOMM70:SARS-CoV-2 9b complex suggests that viral 9b binds to the substrate recognition site of TOMM70 thus competing with substrate proteins involved in the induction of type I IFN synthesis (Jiang HW et al. 2020; Gordon DE et al. 2020a; reviewed in Kreimendahl S & Joachim Rassow J 2020). Structural and biochemical analysis revealed that Ser53 of the viral 9b protein and Glu477 of TOMM70 are crucial for the association of both proteins and recruitment of HSP90 (Gao X et al. 2021; Brandherm L et al. 2021). Circular dichroism experiments and differential scanning calorimetry showed that the 9b:TOMM70 complex is more thermally stable than free TOMM70 (Ayinde KS etal. 2022). Isothermal titration calorimetry (ITC) showed that a synthetic peptide harboring a central segment of 9b binds TOMM70 with nanomolar KD (Gao X et al. 2021). Further, the binding affinity between the C-terminal EEVD motif of HSP90 and the N-terminal TPR clamp domain TOMM70 was decreased when TOMM70 was associated with viral 9b (Gao X et al. 2021). These data suggest that SARS-CoV-2 9b (ORF9b) interaction with TOMM70 inhibits binding of HSP90 to TOMM70.

This Reactome event shows binding of SARS-CoV-2 9b to TOMM70.

Literature References
PubMed ID Title Journal Year
33060197 Comparative host-coronavirus protein interaction networks reveal pan-viral disease mechanisms

Dunham, I, Kehrer, T, Southworth, DR, Alessi, DR, García-Sastre, A, Jura, N, Park, J, Liu, X, Frost, A, Li, Y, Kochs, G, Davies, P, Shokat, KM, Smith, AM, Foussard, H, Beltrao, P, Liu, Y, Koh, C, Vignuzzi, M, Tsui, TKM, Pollard, KS, Williams, DM, Merz, GE, Bouhaddou, M, Faust, B, Vallejo-Gracia, A, Tummino, TA, Li, F, Logue, J, Hemphill, KR, Guo, JZ, Barrio-Hernandez, I, Verba, KA, Shoichet, B, Pospiech, TH, Paulino, J, Ideker, T, Tse, E, Deshpande, I, Chio, CM, Fabius, JM, Geyer, A, Obernier, K, Safari, M, Pourmal, S, Simoneau, CR, Haas, P, Moreno, E, Zhang, Z, Cakir, M, Soucheray, M, Hüttenhain, R, Hiatt, J, Ott, M, Klesh, RJ, Rihn, S, Kortemme, T, Moritz, M, Burness, KA, Kaake, RM, Zhao, J, Carlson-Stevermer, J, Weston, S, Memon, D, Gordon, DE, Reid, E, Roth, TL, Shi, Y, Peden, AA, Azumaya, CM, Trenker, R, Weckstein, AR, Manglik, A, Vallet, T, Fraser, JS, Xu, J, White, KM, Braberg, H, Modak, M, Rathore, U, Batra, J, Wang, F, Hastie, CJ, Grosse, R, Toth, R, Zhang, Y, Li, YL, Goodman, N, Patel, AH, Basler, CF, Whitis, N, Keough, KC, QCRG Structural Biology Consortium, -, Elliott, M, Maures, T, Oki, J, Kim, K, Nowotny, C, Asarnow, D, Chazal, M, Gupta, M, Rassen, JA, McGregor, M, Ummadi, M, Khalid, MM, Flores, S, Frieman, MB, Baillie, C, Moss, FR, Weigang, S, Nguyen, HC, Biel, J, Doan, L, Brown, F, Silvas, JA, Palmarini, M, Chen, J, Saltzberg, D, Rojc, A, Pawar, KI, Giesel, DM, Dorward, M, Sangwan, S, Schulze-Gahmen, U, Ulferts, S, McGrath, M, Shun-Shion, AS, Holden, K, Sali, A, Thomas, PV, Kratochvil, HT, Johnson, C, Cakir, Z, Young, ID, Titus, EW, Schaefer, K, Haupt, R, Wilkinson, SG, Puchades, C, Agard, DA, Marrero, MC, Zoonomia Consortium, -, Peters, JK, Dunham, A, Lopez, KE, Nguyen, P, Bowen, A, Rizo, AN, Burke, D, Zhou, F, Naing, ZZC, Hoppe, N, Brilot, AF, Sun, M, Diwanji, D, Fozouni, P, Rosales, R, Rosenberg, OS, Cheng, Y, Abate, C, Diallo, A, Kuchenov, D, Raggett, S, Karim, MA, Thwin, AC, Berardi, F, Ghoussaini, M, Zhang, K, Stroud, RM, Yu, Z, Eckhardt, M, Braxton, JR, Leech, H, Pulido, EH, Chio, US, O'Meara, MJ, Melo, AA, Miorin, L, Owens, TW, Swaney, DL, Wu, D, Petsalaki, E, Lind, AL, Tutuncuoglu, B, Hodder, AJ, Li, J, Rezelj, VV, Haas, KM, Zhou, Y, Lo, M, Jang, G, Jureka, AS, Billesbølle, C, Krogan, NJ, Jin, M, Dickinson, MS, Jouvenet, N, Herrera, N, Campbell, MG, Lam, VL

Science 2020
32728199 SARS-CoV-2 Orf9b suppresses type I interferon responses by targeting TOM70

Zheng, YX, Tao, SC, Wang, XN, Chen, H, Xie, J, Meng, QF, Jiang, HW, Zhang, J, Qi, H, Zhang, HN, Han, ZG, Wang, PH, Li, Y

Cell Mol Immunol 2020
33990585 Crystal structure of SARS-CoV-2 Orf9b in complex with human TOM70 suggests unusual virus-host interactions

Gao, X, Cui, S, Qin, B, Olieric, V, Wang, M, Zhu, K

Nat Commun 2021
34502139 Phosphorylation of SARS-CoV-2 Orf9b Regulates Its Targeting to Two Binding Sites in TOM70 and Recruitment of Hsp90

Pfaender, S, Brandherm, L, Brüggemann, Y, Kreimendahl, S, Klöhn, M, Rassow, J, Kobaš, AM

Int J Mol Sci 2021
35643212 Binding of SARS-CoV-2 protein ORF9b to mitochondrial translocase TOM70 prevents its interaction with chaperone HSP90

Ayinde, KS, Ramos, CHI, Pinheiro, GMS

Biochimie 2022
Participants
Input
Output
Participates
as an event of
This event is regulated
Negatively by
Regulator
p-S53-9b [cytosol] (Severe acute respiratory syndrome coronavirus 2)
Disease
Name Identifier Synonyms
COVID-19 DOID:0080600 2019 Novel Coronavirus (2019-nCoV), Wuhan seafood market pneumonia virus infection, 2019-nCoV infection, Wuhan coronavirus infection
Authored
Shamovsky, V  (2021-10-27)
Reviewed
Messina, F  (2022-02-18)
Created
Shamovsky, V  (2020-12-17)
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