Fig. 6

Proposed model of H. vulgaris phototransduction cascade. 1) SEC14-like transports a chromophore molecule (represented by a hexagon) to the opsin protein. 2) Light causes a conformational change in the chromophore structure converting rhodopsin to activated metarhodopsin. 3) Gtαi and Gαq activate GMP − PDEα1 or GMP − PDEα2 and PLC, respectively. 4) GMP − PDEα1 and/or GMP − PDEα2 convert cGMP to GMP while ANPR1-like and ANPR1-like2 convert GTP to cGMP. 5) Decrease of cGMP cause the CNG ion channel to close. 6) Metarhodopsin is deactivated by arrestin or phosphorylation by Rh kinase and GRK5-like. GMP − PDEδ has a positive interaction with GKR5-like but neurocalcin-like inhibits phosphorylation and deactivation of metarhodopsin. All genes in this figure are expressed in similar patterns. Blue arrows denote positive interactions or activation while pink lines with flat endings represent inhibition