TABLE 1

Naturally biased signaling

Receptor	Agonist 1	Signaling	Agonist 2	Signaling	Reference
GLP-1	Oxyntomodulin	Preferred cAMP	GLP-1	cAMP/β-Arr1/β-Arr2	Jorgensen et al. (2007)
PAC1	PACAP_1-27	cAMP > IP3	PACAP_1-38	IP3 > cAMP	Spengler et al. (1993), Blechman and Levkowitz (2013)
CCR7	CCL19	β-Arr2 > β-Arr1	CCL21	≠β-Arr2 ≠ β-Arr1	Byers et al. (2008), Hauser and Legler (2016)
P2Y2	ATP	β-Arr1 > β-Arr2	UTP	β-Arr1 = β-Arr2	Hoffmann et al. (2008)
μ-Opioid	β-Endorphin	β-Arr2 > cAMP	Endomorphin-2	cAMP > β-Arr2	Thompson et al. (2015)
CXCR4	Ubiquitin	IP3 > β-Arr2	CXCL12	IP3/β-Arr2	Eby et al. (2017)
Ang II type 1	AT-(1-7)	β-Arr2 > > G_q	Ang II	G_q/β-Arr2	Galandrin et al. (2016a), Teixeira et al. (2017)
PAR1	APC	β-Arr2 > G protein	Thrombin	G protein/β-Arr2	Roy et al. (2016)
Adenosine_A2A	Inosine	ERK1/2 > cAMP	Adenosine	cAMP/ERK1/2	Welihinda et al. (2016)
V₂R	Vasopressin	Prolonged cAMP	Oxytocin	Transient cAMP	Feinstein et al. (2013)

Ang, angiotensin; APC, activated protein C; Arr, arrestin; AT, angiotensin; P2Y2, purinergic receptor Y2; PAC, pituitary adenylate cyclase-activating polypeptide type I; V₂R, vasopressin receptor 2.