The initiation of prokaryotic translation commences with the small subunit and is catalyzed by three translation initiation factors called IF1, IF2, and IF3.

TLS Online TPP Program

#Id: 9338

#Unit 4. Cell Communication and Cell Signaling

Monomeric active forms of all members of the TGF-β family (3 conserved intramolecular disulfide Linkages) contain a conserved cysteine residue that forms a disulfide bond links TGF-β monomers into functional homodimers

and heterodimers

TLS Online TPP Program

#Id: 9339

#Unit 4. Cell Communication and Cell Signaling

TGF-β is synthesized with a, 

250-residue N-terminal prodomain

∼110-residue C-terminal TGF-β domain

TLS Online TPP Program

#Id: 9340

#Unit 4. Cell Communication and Cell Signaling

N-terminal prodomain is required for proper folding and dimerization of the C-terminal TGF-β domain.

TLS Online TPP Program

#Id: 9341

#Unit 4. Cell Communication and Cell Signaling

TGF-β latency

In the Golgi prodomain is proteolytically cleaved from the mature growth factor but remains noncovalently attached even after secretion.

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).