Table 1. Examples of Bacterial Proteins Interfering with UBI/UBL Conjugation to Host Proteins^a.

UBI/UBL target	Bacteria	Extra/intracellular bacteria	Effector	Enzymatic activity	Effect	Refs
UBI	Salmonella Typhimurium	Intracellular	SopA	E3 UBI ligase (HECT)	Regulation of host inflammation	[67]
UBI	EPEC, EHEC	Extracellular	NleL	E3 UBI ligase (HECT)	Regulation of actin pedestal formation	[101]
UBI	EPEC, EHEC	Extracellular	NleG	E3 UBI ligase (RING)	ND	[102]
UBI	Pseudomonas syringae	Extracellular	AvrPtoB	E3 UBI ligase (U-box)	Inhibition of plant pattern-triggered immunity	[103,104]
UBI	Shigella flexneri	Intracellular	OspI	Gln deamidase	Inactivation of UBE2N/UBC13 (E2 UBI enzyme (NF-κB pathway)	[34]
UBI	Shigella flexneri	Intracellular	IpaH1.4	E3 UBI ligase (NEL)	Ubiquitination of LUBAC (NF-κB pathway)	[60]
UBI	Shigella flexneri	Intracellular	IpaH2.5	E3 UBI ligase (NEL)	Ubiquitination of LUBAC (NF-κB pathway)	[60]
UBI	Shigella flexneri	Intracellular	IpaH0722	E3 UBI ligase (NEL)	Ubiquitination of TRAF2 (NF-κB pathway)	[62]
UBI	Shigella flexneri	Intracellular	IpaH9.8	E3 UBI ligase (NEL)	Ubiquitination of NEMO (NF-κB pathway)	[61]
UBI	Salmonella Typhimurium	Intracellular	Ssph1	E3 UBI ligase (NEL)	Ubiquitination of PKN1 (NF-κB pathway)	[105]
UBI	Legionella pneumophila	Intracellular	SdeA	Non-eukaryotic UBI ligase	E1/E2-independent ubiquitination of RAB GTPases and RTN4	[46–48]
UBI	Shigella flexneri	Intracellular	OspG	Kinase	Inhibition of UBCH5 (E2 UBI enzyme; NF-κB pathway)	[63]
UBI	EPEC, EHEC	Extracellular	NleB	Glycosyltransferase	Inhibition of TRAF2 ubiquitination (NF-κB pathway)	[106]
UBI	EPEC	Extracellular	ND	ND	Downregulation of UBE1 and UBA6 (E1 UBI enzymes)	[35]
UBI	EPEC	Extracellular	NleE	Cys methyltransferase	Inactivation of TAB2 and TAB3 (NF-κB pathway)	[67,107]
UBI	Legionella pneumophila	Intracellular	SidJ	Deubiquitylase	ND	[50]
UBI	Shigella flexneri	Intracellular	ShiCE	Deubiquitylase	ND	[54]
UBI	Chlamydia trachomatis	Intracellular	ChlaDUB1	Deubiquitylase	Inhibition of NF-κB pathway activation	[108,109]
UBI	Burkholderia pseudomallei	Extracellular	CHBP	Gln deamidase	Deamidation of UBI	[57]
SUMO	Listeria monocytogenes	Intracellular	LLO	Pore-forming toxin	Downregulation of UBE2I/UBC9 (E2 SUMO enzyme)	[25]
SUMO	Clostridium perfringens	Extracellular	PFO	Pore-forming toxin	Downregulation of UBE2I/UBC9 (E2 SUMO enzyme)	[25]
SUMO	Streptococcus pneumoniae	Extracellular	PLY	Pore-forming toxin	Downregulation of UBE2I/UBC9 (E2 SUMO enzyme)	[25]
SUMO	Shigella flexneri	Intracellular	ND/Ca2+ influx	ND	Proteolytic cleavage of UBA2/SAE2 (E1 SUMO enzyme)	[39]
SUMO	Salmonella Typhimurium	Intracellular	ND/miRNAs	ND	Downregulation of UBE2I/UBC9 (E2 SUMO enzyme)	[38]
SUMO	Xanthomonas euvesicatoria	Extracellular	XopD	DeSUMOylase	DeSUMOylation of SIERF4 (plant immune response)	[51,52]
NEDD8	EPEC	Extracellular	CIF	Gln deamidase	Deamidation of NEDD8	[57,58]
NEDD8	Chlamydia trachomatis	Intracellular	ChlaDUB1	DeNEDDylase	Inhibition of NF-κB pathway activation	[108,109]

^aAbbreviations: EPEC, enteropathogenic Escherichia coli; EHEC, enterohemorrhagic Escherichia coli; HECT, homologous to the E6-AP C terminus; ND, not determined; NEL, novel E3 ligase; RING, really interesting new gene.