Pyruvate Carboxylase

a mitochondrial enzyme that requires the coenzyme biotin, converts the pyruvate to oxaloacetate

TLS Online TPP Program

#Id: 1374

#Unit 4. Cell Communication and Cell Signaling

Erythropoietin,

• secreted by kidney cells

• promotes proliferation and differentiation of erythroid progenitor cells in the bone marrow to increase the number of mature red cells in the blood

TLS Online TPP Program

#Id: 1375

#Unit 4. Cell Communication and Cell Signaling

STAT5 becomes activated in erythroid progenitor cells,  induces expression of the protein Bcl-xL.

TLS Online TPP Program

#Id: 1376

#Unit 4. Cell Communication and Cell Signaling

Two mechanisms for terminating cytokine signal transduction

1.  Short-term regulation

2.  Long-term regulation

TLS Online TPP Program

#Id: 1377

#Unit 4. Cell Communication and Cell Signaling

Short-term regulation: 

JAK2 deactivation by SHP1 phosphatase

TLS Online TPP Program

#Id: 1378

#Unit 4. Cell Communication and Cell Signaling

Long-term regulation: 

• SOCS proteins

• Targets the receptor as well as JAK2 for degradation by the ubiquitin-proteasome pathway

TLS Online TPP Program

#Id: 1379

#Unit 4. Cell Communication and Cell Signaling

The rate-limiting step in actin filament assembly is the formation of a short actin oligomer (nucleus).