Table 1.

PD-L1 modifications and their downstream impact.

Posttranslational Modification	Regulator	Downstream Impact	References
Glycosylation	STT3A	Transfers the core glycan structure to PD-L1, resulting in PD-L1 protein N-glycosylation and stabilization.	[27]
	B3GNT3	N192 and N200 of PD-L1 glycosylation are required for PD-L1–PD-1 interaction.	[37]
(De)Ubiquitination	β-Trcp	Promotes PD-L1 poly-ubiquitination and degradation following GSK3β-mediated T180 and S184 phosphorylation of PD-L1.	[24]
	Cullin-3-SPOP	Destabilization of PD-L1 through proteasomal degradation.	[30]
	STUB1	Poly-ubiquitinates and down-regulates PD-L1 through proteasomal degradation.	[53]
	CSN5	Deubiquitination of PD-L1 to enhance the stability of PD-L1.	[32]
	USP9X	Deubiquitinates and stabilizes PD-L1.	[33]
	USP22	Deubiquitinates and stabilizes PD-L1.	[34,35]
	OTUB1	Deubiquitinates and stabilizes PD-L1.	[36]
Phosphorylation	GSK3β	Phosphorylation of PD-L1 at T180 and S184 recruits b-TrCP for PD-L1 degradation.	[24]
	JAK1	Phosphorylation on Y112 enhances STT3A-mediated PD-L1 glycosylation and trafficking to the cell surface.	[28]
	AMPK	Phosphorylates PD-L1 at S195 to induce abnormal ER mannose trimming and promote PD-L1 degradation through the ERAD pathway.	[29]
Palmitoylation	ZDHHC9	PD-L1 palmitoylation at C272 maintains its protein stability and cell surface distribution.	[55]
	DHHC3	PD-L1 palmitoylation at C272 promotes PD-L1 storage and stabilization.	[56]
(De)Acetylation	HDAC2	PD-L1 is translocated into the nucleus and binds to DNA to regulate the expression of multiple immune-response-related genes.	[62]
	P300	Acetylated PD-L1 at the K263 site to maintain PD-L1 in cytoplasm.	[62]