Fig. 2.
Impact of homo- and heterodimerization in GLP-1R signaling. Arr3 = Arrestin3. Disruption of GLP-1R homodimer formation severely inhibits GLP-1-mediated Ca2+ mobilization, suggesting that homodimerization is involved in this signaling pathway. GLP-1 has also been shown to induce heterodimerization of GLP-1R and GIPR. Coexpression of GIPR with GLP-1R attenuates GLP-1-mediated cAMP production, arrestin3 recruitment, Ca2+ mobilization, and GLP-1R internalization. This suggests that GIPR acts as a negative regulator of GLP-1R signaling.