Microtubules can be stabilized by side-binding microtubule associated proteins (MAPs).

TLS Online TPP Program

#Id: 9373

#Unit 4. Cell Communication and Cell Signaling

Smad7 binds to the activated RI receptors and blocks its ability to phosphorylate Smad2 or Smad3. 

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#Unit 4. Cell Communication and Cell Signaling

Like SOCS proteins in the cytokine signaling, 

Smad7 also recruits an E3 ubiquitin ligase that targets TGF-β receptors for degradation.

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#Id: 9446

#Unit 4. Cell Communication and Cell Signaling

The cytokines form a family of relatively small, secreted signaling molecules:

Contain about 160–200 AA

4 long, conserved α helices

Control growth and differentiation

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#Id: 9447

#Unit 4. Cell Communication and Cell Signaling

Large family of cytokines:

Interleukins

Interferons

Growth hormone

Prolactin

G-CSF

Thrombopoietin

Erythropoietin

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#Unit 4. Cell Communication and Cell Signaling

Receptor Homodimerization 

Cytokines (erythropoietin) activate receptors by forming dimers of two identical cytokine receptor proteins

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#Id: 9450

#Unit 4. Cell Communication and Cell Signaling

Receptor hetero-dimerization or hetero-oligomerization 

Other cytokines (interleukins and interferons) bind simultaneously to two or more different cytokine receptors