Helicases are loaded during G1 are only activated to unwind DNA and initiate replication after cells pass from the G1 to the S phase of the cell cycle in effect with S phase CDKC

TLS Online TPP Program

#Id: 1464

#Unit 4. Cell Communication and Cell Signaling

Each classical cadherin molecule contains: 

A single transmembrane domain

A relatively short C-terminal cytosolic domain

Five extracellular “cadherin” domains (called EC1–EC5)

TLS Online TPP Program

#Id: 1465

#Unit 4. Cell Communication and Cell Signaling

Three classes of classical cadherins: 

E-cadherin -present on many types of epithelial cells

N-cadherin - present on nerve, muscle and lens cells

P-cadherin - present on cells in the placenta & epidermis

TLS Online TPP Program

#Id: 1466

#Unit 4. Cell Communication and Cell Signaling

Nonclassical cadherins include proteins:

• Protocadherins found in the brain

• Desmocollins and desmogleins that form desmosomes

TLS Online TPP Program

#Id: 1467

#Unit 4. Cell Communication and Cell Signaling

Epithelial-to-mesenchymal transition is associated with a reduction in the expression of E-cadherin.

TLS Online TPP Program

#Id: 1468

#Unit 4. Cell Communication and Cell Signaling

A cadherin-family member CDHR3, highly expressed in epithelial cells in the human airway, as a receptor for RV-C (virulent class C rhinoviruses).

TLS Online TPP Program

#Id: 1469

#Unit 4. Cell Communication and Cell Signaling

In cultured cells, C → Y mutation in the EC5 domain of CDHR3 increases the cell-surface expression of CDHR3 and the binding and replication of RV-C.