The Golgi consists of four functionally distinct regions:

a. Cis compartments

b. Medial compartments

c. Trans compartments

d. Trans-Golgi network

TLS Online TPP Program

#Id: 1355

#Unit 4. Cell Communication and Cell Signaling

MEK, a dual-specificity protein kinase

TLS Online TPP Program

#Id: 9032

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9033

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9034

#Unit 4. Cell Communication and Cell Signaling

Ligand binding depends on: 

Multiple weak, noncovalent forces

Molecular complementarity

TLS Online TPP Program

#Id: 9035

#Unit 4. Cell Communication and Cell Signaling

Binding of the ligand to the receptor causes the receptor to change from an inactive conformation (R) to an active conformation (R*). Only the active R* conformation of the receptor can trigger the signal transduction pathway.

TLS Online TPP Program

#Id: 9036

#Unit 4. Cell Communication and Cell Signaling

The affinity of a signal molecule’s binding to its receptor is quantified by the dissociation constant for binding (Kd).