Capacitation is a transient event, and sperm are given a relatively brief window of competence during which they can successfully fertilize the egg. As the sperm reach the ampulla, they acquire competence—but they lose it if they stay around too long

TLS Online TPP Program

#Id: 9367

#Unit 4. Cell Communication and Cell Signaling

BMP proteins, activate a different set of receptors that are similar to the TGF-β RI and RII proteins but phosphorylate other R-Smads, Smad1, Smad5, & Smad8

TLS Online TPP Program

#Id: 9368

#Unit 4. Cell Communication and Cell Signaling

Smad4 was originally called DPC (deleted in pancreatic cancer)

TLS Online TPP Program

#Id: 9369

#Unit 4. Cell Communication and Cell Signaling

Negative regulators of TGF-β signaling are induced by TGF-β signaling (Example of Negative feedback): 

Ski 

SnoN 

I-Smads (Smad7)

TLS Online TPP Program

#Id: 9370

#Unit 4. Cell Communication and Cell Signaling

SnoN and Ski trigger abnormal cell proliferation by blocking the Smad-complex.

TLS Online TPP Program

#Id: 9371

#Unit 4. Cell Communication and Cell Signaling

TLS Online TPP Program

#Id: 9372

#Unit 4. Cell Communication and Cell Signaling

Ski recruits N-CoR, which binds directly to mSin3A; mSin3A interacts with HDAC, that promotes histone deacetylation on nearby promoters, repressing gene expression