Cytokine Signaling

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Cytokine Signaling
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Types of receptors

• Protein tyrosine kinase receptors with intrinsic
  kinase activity
• Insulin, EGF, PDGF, CSF-1 etc.
• Protein serine kinase receptors with intrinsic
  kinase activity
• MIS, TGFb, activin, inhibin etc.
• Receptors without intrinsic kinase activity
• This is the large, heterogeneous group called the
  cytokine receptor super family
• G-protein coupled receptors and ion-gated
  receptors

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Types of receptors
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Protein tyrosine kinase receptors
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PTK receptor activating MAP kinase pathway
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PTK receptor activating Pi-3 kinase pathway
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SH2 domain containing protein recognition of
phosphotyrosines
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PTK signaling 1o and 2o signals
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Cytokine signaling mechanisms

• Cytokines represent a diverse number of
  molecules.
• The super family of cytokine receptors more
  specifically refers to those cytokines that
  signal via the Jak-STAT pathway
• These include Interleukins 2, 3, 4, 5, 6, 7, 9,
  11, 12, 13, 15, and G-CSF, LIF and the
  interferons
• In addition, growth hormone, prolactin,
  erythropoietin, leptin, thrombopoietin
• Many growth factor signal pathways
  cross-communicate with the STAT pathway.

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General scheme for all MAP-kinase pathways
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Receptor activation of intracellular signaling
pathways
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PTK vs. cytokine pathways
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G-protein coupled receptors
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Cytokines and Leydig cells
Immune-Endocrine control of Leydig cell function
Overview and significance of Immune-endocrine
interactions in the regulation of Leydig cell
function