Table 2.
Role of viral mitochondrial proteins in replication and transformation.
| Viral protein | Effects on virus replication | Role in transformation |
|---|---|---|
| HTLV-1 p13 | Not required for replication in vitro (Derse et al., 1997), but necessary for virus persistence in in vivo rabbit model (Hiraragi et al., 2006); mechanism unknown | Proposed negative role: interferes with transformation of fibroblasts by Myc and Ras; favors death of transformed but not normal T-cells, possibly by raising mitochondrial ROS production (reviewed by Silic-Benussi et al., 2010a) |
| EBV BHRF1 | Not required for virus replication (Altmann and Hammerschmidt, 2005) | Required for transformation of resting B-cells, but dispensable for transformation of activated B-cells (Altmann and Hammerschmidt, 2005) |
| KSHV K7 | Not required for virus replication (Liang et al., 2015; Gallo et al., 2017) | Possible negative role through interference with transforming activity of vGPCR (Feng et al., 2008a) |
| KSHV KS-Bcl-2 | Required for efficient virus replication (Gelgor et al., 2015; Liang et al., 2015; Gallo et al., 2017) Not required for establishment of latent infection (Gelgor et al., 2015) | Positive role likely, through inhibition of apoptosis in infected cells |
| HBV HBx | Favors viral replication; enhances viral polymerase activity through Ca2+ signaling (Lucifora et al., 2011) | Transforms cells in vitro and causes tumors in transgenic mice (reviewed by Levrero and Zucman-Rossi, 2016) |
| HBV Pol | Needed for packaging of pregenomic RNA and reverse transcription into dsDNA genome (Bartenschlager and Schaller, 1992) | Not defined |
| HCV Core | Forms virion capsid (reviewed by Scheel and Rice, 2013) | Transforms cells in vitro and causes tumors in transgenic mice (reviewed by Banerjee et al., 2010) |
| HCV p7 | Viroporin required for virion assembly and release (reviewed by Madan and Bartenschlager, 2015) | Not defined |
| HCV NS3/4A | Required for viral RNA replication, polyprotein processing and virion assembly (reviewed by Morikawa et al., 2011); cleavage of MAVS proposed to favor immune evasion (Horner et al., 2011) | Not defined; NS3 alone transforms cells in vitro (Sakamuro et al., 1995) |
| NS4A | Forms complex with NS3 (see above) | Not defined |
| HPV E1∧E4 | May promote virion release through perturbation of the cytokeratin network (Raj et al., 2004) | Not defined |
| HPV E2 | Essential for coordination of late events of viral replication (reviewed by Graham, 2016) | Negative role, through inhibition of E6 and E7 expression (reviewed by Woodman et al., 2007) |