Pathway
The phototransduction cascade
The visual pigment (rhodopsin in rods) consists of an 11-cis-retinal (11cRAL) chromophore covalently attached to a GPCR opsin family member via a Schiff base linkage. Upon photon absorption, 11cRAL isomerizes to all trans retinal (atRAL), changing the conformation of opsin to a form that can activate the regulatory G protein transducin (Gt). The alpha subunit of Gt activates phosphodiesterase which hydrolyses cGMP to 5'-GMP. A high level of cGMP keeps cGMP-gated cation channels open, so lower cGMP levels close these channels and hyperpolarize the cell. The hyperpolarization spreads passively to the synapse located at the opposite end of the rod, where it subsequently closes voltage-gated calcium channels. Vesicular release of the neurotransmitter glutamate subsides as the intracellular calcium levels drop. This diminution of neurotransmitter release relays the light signal to postsynaptic neurons. The events below describe activation, inactivation, recovery and regulation of the phototransduction cascade in rods.
What the reference databases state
Statements
31 statements
31 statements · 1 reference database · Subject: The phototransduction cascade · Sources: Reactome
- CALM1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- CAMKMT participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- CNGA1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- CNGB1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- FNTA participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- FNTB participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GNAT1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GNB1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GNGT1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GRK1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GRK7 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GUCA1A participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
Show the remaining 19
- GUCA1B participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GUCA1C participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GUCY2D participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- GUCY2F participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- METAP1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- METAP2 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- NMT1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- NMT2 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- PDE6A participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- PDE6B participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- PDE6G participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- PPEF1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- PRKCA participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- PRKCQ participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- RCVRN participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- RGS9BP participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- RHO participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- SAG participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only
- SLC24A1 participates in The phototransduction cascadeProteinReactome R-HSA-2514856Inferred only