The Ramachandran Principle is that alpha helices, beta strands, and

turns are the most likely conformations for a polypeptide chain to 

adopt, because most other conformations are impossible due to

steric collisions between atoms. 

TLS Online TPP Program

#Id: 9686

#Unit 4. Cell Communication and Cell Signaling

Fat and muscle cells express large amounts of the insulin-responsive glucose transporter GLUT4

TLS Online TPP Program

#Id: 9687

#Unit 4. Cell Communication and Cell Signaling

In resting cells, the majority of the GLUT4 protein is

localized to specialized GLUT4 storage vesicles (GSVs)

TLS Online TPP Program

#Id: 9688

#Unit 4. Cell Communication and Cell Signaling

GSVs tethered to the Golgi matrix, by a protein termed TUG (Tether containing a UBX domain for GLUT4).

TLS Online TPP Program

#Id: 9689

#Unit 4. Cell Communication and Cell Signaling

Binding of insulin to its receptor triggers activation of a protease that catalyzes a site-specific endoproteolytic cleavage of TUG

TLS Online TPP Program

#Id: 9690

#Unit 4. Cell Communication and Cell Signaling

Released N-terminal TUG fragment bind to the kinesin, initiates the microtubule-based movement of the GSVs to the plasma membrane.

TLS Online TPP Program

#Id: 9691

#Unit 4. Cell Communication and Cell Signaling

Movement of the GSVs to the plasma membrane is regulated by two monomeric GTP-binding proteins -RalA and Rab10