Piwi-associated RNAs, piRNA, are a special class of miRNA found in germ cells have features distinct from miRNAs.  siRNA (small interfering RNA), which is typically produced during a virus infection.

TLS Online TPP Program

#Id: 9317

#Unit 4. Cell Communication and Cell Signaling

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.