Parity rules by Erwin Chargaff

Rule of complementarity (First parity rule)

Rule of Equal amount applies more closely to introns than to exons (Second parity rule)

Cluster rule – Purines in nontemplate strand applies more closely to Exons (Third parity rule)

GC Rule- GC content tends to be greater in exons than in introns (Fourth parity rule

TLS Online TPP Program

#Id: 1373

#Unit 4. Cell Communication and Cell Signaling

 Phosphorylated STAT dissociates spontaneously from the receptor, dimerize & move into the nucleus.

 

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