Loss-of-function mutations in PTC1 permit cell

proliferation in the absence of an Hh signal

TLS Online TPP Program

#Id: 10092

#Unit 4. Cell Communication and Cell Signaling

Inside-out signaling

intracellular signaling pathways can, via adapter proteins, modify the ability of integrins to bind

to their extracellular ligands

TLS Online TPP Program

#Id: 10093

#Unit 4. Cell Communication and Cell Signaling

Integrin exist in two conformations: 

Inactive, low-affinity, “bent” conformation  

Active, high-affinity, “extended” conformation

TLS Online TPP Program

#Id: 10094

#Unit 4. Cell Communication and Cell Signaling

Activation of integrins involves:

Conformational changes near the propeller and 

 βA domains

Separation of the transmembrane and cytoplasmic domains

TLS Online TPP Program

#Id: 10095

#Unit 4. Cell Communication and Cell Signaling

Hemidesmosomes are integrin-containing anchoring junctions that attach cells to elements of the underlying extracellular matrix.

TLS Online TPP Program

#Id: 10096

#Unit 4. Cell Communication and Cell Signaling

Integrins have an important function in neuroregeneration after injury of the peripheral nervous system.

TLS Online TPP Program

#Id: 10097

#Unit 4. Cell Communication and Cell Signaling

Three major classes of animal-cell junctions: 

1. Anchoring junctions

2. Tight junctions

3. Gap junctions