Facilitation model =  Species are facilitated by previous colonists

Inhibition model =  They are inhibited by the action of previous colonists

Tolerance model  =  They are unaffected by  previous colonists/ New pioneer neither inhibit nor facilitate 

TLS Online TPP Program

#Id: 9342

#Unit 4. Cell Communication and Cell Signaling

Prodomain prevents the latent TGF-β 

from binding to a cell-surface receptor.

TLS Online TPP Program

#Id: 9343

#Unit 4. Cell Communication and Cell Signaling

Prodomain forms disulfide linkages that localize the latent TGF-β to the surface of the secreting cell (GARP), to a nearby cell, or to the extracellular matrix (LTBP).

TLS Online TPP Program

#Id: 9345

#Unit 4. Cell Communication and Cell Signaling

TGF-β activation

By cytoskeletal force transmitted by integrins

TLS Online TPP Program

#Id: 9346

#Unit 4. Cell Communication and Cell Signaling

The prodomains of TGF-β1 and TGF-β3 contain a RGD motif, that allows them to bind to integrins.

TLS Online TPP Program

#Id: 9347

#Unit 4. Cell Communication and Cell Signaling

During cell migration, a tensile force is generated which physically distorts the prodomain and frees the active TGF-β dimer, initiating TGF-β signaling.

TLS Online TPP Program

#Id: 9348

#Unit 4. Cell Communication and Cell Signaling

3 separate TGF-β receptor proteins participate in binding TGF-β and activating signaling:

RI, RII, and RIII