Table 1.

GRK isoforms and their established functions in immune cells and inflammation.

GRK Isoform	Interacting Partner(s)	Associated Signalling Pathway/Cellular Response	References
GRK2	NF-kB p105 subunit and inhibitor (IkB-α) phosphorylation	TLR4-induced and Tumor Necrosis Factor-α (TNF-α) pathways	[79,81,82]
	p38 phosphorylation Raf1, MEK1, ERK2, RhoA, RKIP, GIT	P38 mitogen-activated protein kinases (MAPK) pathways Extracellular signal-regulated kinase (ERK) pathways	[83,84,85]
	Serine-threonine kinase Akt phosphorylation	Akt-nitric oxide (NO) pathways	[86,87]
	Ezrin/radixin/moesin phosphorylation	Actin cytoskeleton	[64,65]
	ADP ribosylation factor (ARF)-specific GTPase-activating proteins (GIT)	Focal adhesion dynamic	[63,88]
	Histone deacetylase 6 (HDAC6) phosphorylation	Microtubules network	[89]
	Heat shock protein 90 (Hsp90)	Regulation of GRK expression	[90]
	Receptor-regulated Smads (R-Smads) phosphorylation	Transforming growth factor β (TGF-β) pathways	[91,92]
GRK3	HSP90	Regulation of GRK expression	[90]
GRK5	ERM (moesin phosphorylation)	Actin cytoskeleton	[69]
	GIT1	Regulation of receptor endocytosis	[88]
	HSP90, HSP70	Regulation of GRK expression and CXCR4 endocytosis
	NF-kB p105 subunit and IkB-α phosphorylation	TLR4-induced and TNF-α pathways	[90,91]
	Src Tyrosine kinase	GRK phosphorylation and neutrophils exocytosis	[93]
GRK6	HSP90	Regulation of GRK expression	[90,94]