Author Question: Explain how hematopoiesis uses autocrine, paracrine, and juxtacrine signaling. Choose one and ... (Read 46 times)

biggirl4568 · **on:** Jun 25, 2018

Explain how hematopoiesis uses autocrine, paracrine, and juxtacrine signaling. Choose one and provide an example of signaling through that pathway.

What will be an ideal response?

Question 2

Explain the JAK-STAT signaling pathway, and describe how it can contribute to disease.

What will be an ideal response?

perkiness · **Reply #1 on:** Jun 25, 2018

Answer to Question 1

Answer: Autocrine signaling: produced by and act on the same cell. Example: Rarely seen; T-cells and IL-2.
Paracrine signaling: produced by and act on adjacent cells. Example: progenitors and precursors adjacent to the BM stroma.
Juxtacrine signaling: The cytokine remains membrane-bound, which requires interaction between membrane and membrane receptors to achieve the desired effect. Example: stem cells and SCF or FL.

Answer to Question 2

Answer: JAK: Janus family PTKs (protein tyrosine kinases) interact with the STAT transcription factors (signal transducers and activators of transcription). Once STAT proteins are phosphorylated by activated JAK kinases, they dimerize, translocate to the nucleus, bind to cytokine-specific DNA sequences, and activate (or inhibit) specific gene expression. Abnormalities in this pathway have been shown to cause polycythemia vera and other myeloproliferative disorders.