Table 1.

Effector proteins employed by bacterial pathogens to escape or hijack components of the host ubiquitin machinery

Pathogen	Effector	Protein type	Mechanism of action	Reference
Salmonella Typhimurium	SopA	HECT‐like	Ubiquitylates host E3 ligases TRIM65 and TRIM56 thereby blocking the expression of interferon‐γ and nucleic acid sensing receptor STING	Fiskin et al, (2017)
	SspH1	Novel E3 ligase family	Ubiquitylates serine/threonine kinase PKN1 resulting in its proteasomal degradation and suppression of NF‐kB pathway	Keszei et al, (2014)
	SspH2	Novel E3 ligase family	Ubiquitylates and activates NOD1 signaling	Bhavsar et al, (2013)
	SlrP	Novel E3 ligase family	Ubiquitylates host thioredoxin (TXN) inducing host cell death	Bernal‐Bayard and Ramos‐Morales (2009)
	SseL	Deubiquitinase	Removes Ub aggregates on Salmonella and SCVs	Mesquita et al, (2012)
Legionella pneumophila	RavZ	Cysteine protease	Inhibits recruitment of LC3 to LCV by irreversibly deconjugating LC3 from PE; Inhibits recruitment of Ub to LCV via unknown mechanism	Choy et al, (2012); Kubori et al, (2017)
	RavD	Deubiquitinase	RavD specifically hydrolyzes Met1‐linked Ub chains directly antagonizing LUBAC activity and thus activation of NF‐kB	Wan et al, (2019)
Shigella flexneri	IpaH 1.4	Novel E3 ligase family	Interacts with HOIL and conjugate K48 chains to the catalytic domain of HOIP, thereby triggering its proteasomal degradation	de Jong et al, (2016)
	IpaH 2.5	Novel E3 ligase family	Interacts with HOIL and conjugate K48 chains to the catalytic domain of HOIP, thereby triggering its proteasomal degradation	de Jong et al, (2016)
	IpaH 4.5	Novel E3 ligase family	Binds to p65 subunit of NF‐κB and modulates inflammatory response; Promotes K48 polyubiquitylation mediated degradation of TBK1, thereby shutting down the host anti‐bacterial response	Wang et al, (2013) and Zheng et al, (2016)
	IpaH 9.8	Novel E3 ligase family	Ubiquitylates NEMO leading to its proteasomal degradation, thereby inhibiting the NF‐κB signaling pathway	Ashida et al, (2010)
	IpaH 0722	Novel E3 ligase family	Inhibits PKC‐mediated activation of NF‐κB by ubiquitylating TRAF2 for proteasomal degradation	Ashida et al, (2013)
	IcsB	Fatty acyltransferase	Represses the recruitment of LC3 and NDP52 to Shigella; Escapes host autophagy indirectly by mediating fatty acylation and inactivation of CHMP5 protein	Baxt and Goldberg (2014); Liu et al, (2018)
Listeria monocytogenes	ActA	Actin assembly‐inducing protein	Recruits Arp2/3 complex and Ena/VASP to disguise the bacterial surface from autophagic recognition	Yoshikawa et al, (2009)
Mycobacterium tuberculosis	SapM	Acid phosphatase	Prevents fusion of lysosomes with mycobacterium containing phagosomes	Zulauf et al, (2018)
	PknG	Ser‐Thr protein kinase	Ubiquitylation of TRAF2 and TAB1 resulting in their proteasomal degradation	Wang et al, (2021)
Group A Streptococcus (GAS)	SpeB	Cysteine protease	Degrades p62, NDP52, and NBR1 in the host cytosol	Barnett et al, (2013)
Rickettsia parkeri	OmpB	Outer membrane protein	Acts as a protective shield obstructing recognition by the autophagy machinery	Engstrom et al, (2019)
	PKMT1/2	Lysine methlytransferase	Modifies the lysine of outer membrane proteins with methyl groups and prevents their recognition by the host ubiquitin machinery	Engstrom et al, (2021)