Table 3.

An overview of the 19S related PTMs with known target and effect.

	Modification		Target	Cell type/ tissue	Enzyme(s)	Effect	Section	References
19S	Activating	Phosphorylation	RPT1 (Nucleus)	Human HEK293 and HeLa cells	UBLCP1	Phosphatase UBLCP1 downregulation → proteasome activity ↑, 26S proteasome assembly, ubiquitinated protein degradation ↑	2.3.1	Guo et al., 2011; Sun et al., 2017
			RPT3	Human HaCaT and MDA-MB-468 cells	DYRK2	ChT-L activity*↑, substrate translocation and degradation ↑	2.3.2	Guo et al., 2016; Banerjee et al., 2018
			RPT6	Human HEK293 cells, rat NRK and ST14A cells, porcine myocardium and yeast	PKA and PP1γ	ChT-L and T-L activities*↑, 26S proteasome assembly ↑	2.3.3	Satoh et al., 2000; Zhang et al., 2007; Lin et al., 2013; Marquez-Lona et al., 2017
				Human HEK293 cells, rat hippocampal and cortical neurons and amygdala	CaMKII	ChT-L activity*↑, ubiquitinated protein degradation ↑		Djakovic et al., 2009; Bingol et al., 2010; Jarome et al., 2013
			RPN6	Human HEK239 and SH-SY5Y cells, mouse C2C12 and primary hepatocytes	PKA	ATPase activity ↑, proteasome activity ↑, ubiquitinated protein degradation ↑, short-lived and aggregation-prone protein degradation ↑	2.3.4	Lokireddy et al., 2015; VerPlank et al., 2019
	Suppressing		RPT5	Human HEK293 and HeLa cells, mouse MEF cells	ASK1	RPT5 ATPase activity ↓, proteasome activity ↓, (non)ubiquitinated protein degradation ↓	2.4.1	Um et al., 2010
			RPN2	Human HeLa cells	p38 MAPK	Proteasome activity ↓, (non)ubiquitinated protein degradation ↓	2.4.1	Lee et al., 2010
		O-GlcNAcylation	RPT2	Human HUVEC cells, rat NRK cells, mouse aorta	OGT and OGA	ATPase activity ↓, ChT-L activity ↓, ubiquitinated protein degradation ↓	2.4.2	Zhang et al., 2003; Keembiyehetty et al., 2011; Liu et al., 2014
		Carbonylation	RPT3	Human SH-SY5Y cells	-	RPT3 ATPase activity ↓, ubiquitinated protein degradation ↓	2.4.3	Ishii et al., 2005
		15d-PGJ2	Several subunits	Human endothelial cells	-	ChT-L activity*↓, ubiquitinated protein degradation ↓	2.4.4	Marcone, 2016
		S-glutathionylation	RPN2	Human HEK293 cells and neutrophils, mouse lung	-	ChT-L and T-L activities*↓	2.4.5	Zmijewski et al., 2009
		Ubiquitination	RPN10	Human HEK293 cells, yeast and drosophila	RSP5 and UBP2, UBE3C, UBE3A	Substrate binding ↓, ubiquitinated protein degradation ↓, loss 26S and Dsk2 association, RPN10 degradation ↑	2.4.6	Crosas et al., 2006; Isasa et al., 2010; Piterman et al., 2014; Zuin et al., 2015; Keren-Kaplan et al., 2016
			RPN13	Human HEK293 cells	UBE3C	Substrate binding ↓, ubiquitinated protein degradation ↓	2.4.7	Besche et al., 2014
	#	N-myristoylation	RPT2	Yeast	-	Nuclear proteasome localization	2.5.1	Kimura et al., 2012
		Phosphorylation	RPN8	Human breast epithelial (cancer) cell lines	-	Cytoplasmic localization, loss 26S association	2.5.2	Thompson et al., 2004
			RPN3	Human HEK293 cells and mouse MEF cells	CKII (indirect)	Proteasome turnover	2.1.5	Tomita et al., 2019

In some cases only the proteasome complex is known as PTM target rather than a specific subunit. The cell types and/or tissues in which the modification is observed, as well as the involved enzymes are mentioned. (In some cases studied with purified proteasomes). Proteasome activity: all three proteolytic activities;

^#neither activating nor suppressing;

^*only measured enzymatic activity; - unknown.