TRCF binds to double-stranded DNA upstream of the polymerase and uses the ATPase motor to translocate along the DNA until it encounters the stalled RNA polymerase.

TLS Online TPP Program

#Id: 9318

#Unit 4. Cell Communication and Cell Signaling

Rapid termination mechanisms of the Rhodopsin Signalling:

1.GAP that inactivates Gαt·GTP

2.Ca2+ -sensing proteins that activate Guanylate Cyclase

3.Rhodopsin Phosphorylation and Binding of Arrestin

TLS Online TPP Program

#Id: 9319

#Unit 4. Cell Communication and Cell Signaling

Gαt contains an intrinsic GTPase activity by GAP complex, RGS9-Gβ5 triggers the rapid inactivation of the PDE

TLS Online TPP Program

#Id: 9320

#Unit 4. Cell Communication and Cell Signaling

Light-triggered closing of the cGMP-gated cation

channels causes a drop in the cytosolic Ca2+ concentration inside the rod cell.

TLS Online TPP Program

#Id: 9321

#Unit 4. Cell Communication and Cell Signaling

Low intracellular Ca2+ concentration is sensed by a class of Ca2+ -binding proteins known as guanylate cyclase–activating proteins.

TLS Online TPP Program

#Id: 9322

#Unit 4. Cell Communication and Cell Signaling

Guanylate cyclase–activating proteins, 

bind to guanylate cyclase and stimulate its activity, elevating cGMP level and causing the cGMP-gated ion channels to reopen.

TLS Online TPP Program

#Id: 9323

#Unit 4. Cell Communication and Cell Signaling

Terminate the visual response involves phosphorylation of activated (R*) rhodopsin, but not its dark (R) form