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Signaling Machinery The Signals The Receivers

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Presentation on theme: "Signaling Machinery The Signals The Receivers"— Presentation transcript:

1 Signaling Machinery The Signals The Receivers
Peptides & small organic molecules (hormones, amines) Signaling molecules are called ligands in general The Receivers Large proteins (protein complexes) Ligand binding alters conformations resulting in conveyance of signal

2 A Ligand Bound to Its Receptor
Figures\Chapter15\High-Res\life7e-fig jpg

3 Cell Signaling Cell A Cell B Changes in Cell Fate Differentiation
Ligand activates receptor Ligand secreted Receptor Cell A Modulate activity of existing proteins Cell B Signaling cascades initiated Protein synthesis Gene Activation Changes in Cell Fate Differentiation Migration Proliferation

4 Categories of Signaling Molecules
Growth factors (proliferation/differentiation) FGF, EGF, TGF, NGF, peptide hormones Retinoids/Steroids RA, Testosterone, Cortisone Differentiation Wnt, Hedgehog, Delta Cytokines Interferons, interleukins Migration Semaphorins, Ephrins Neurotransmitters Catecholamines, NO Other Odorants, capsaicin

5 Categories of Receptors
Cytoplasmic/Nuclear Bind membrane soluble ligands – steroids/retinoids Directly affect transcription Transmembrane Receptor tyrosine kinases – growth factors Receptor serine kinases – growth factors Kinase-associated receptors - cytokines Seven-pass – neurotransmitters, peptide hormones Ligand-gated channels – neurotransmitters, ions Other – cell-associated ligands

6 Signaling Modes Autocrine Juxtacrine Paracrine
Signal is received by secreting cell (as well as other cells) Juxtacrine Signal is transmitted only short distances to neighboring cells Signaling molecule is membrane anchored or associated with ECM Paracrine Signaling at a distance from source Growth factors, hormones, cytokines, etc. Figures\Chapter15\High-Res\life7e-fig jpg

7 Two Locations for Receptors
Figures\Chapter15\High-Res\life7e-fig jpg

8 A Cytoplasmic Receptor
Figures\Chapter15\High-Res\life7e-fig jpg

9 A Gated Ion Channel Figures\Chapter15\High-Res\life7e-fig jpg

10 A Protein Kinase Receptor
Figures\Chapter15\High-Res\life7e-fig jpg

11 A Protein Kinase Cascade
Figures\Chapter15\High-Res\life7e-fig jpg

12 G-Protein-Linked Receptor (7 Pass)
Figures\Chapter15\High-Res\life7e-fig jpg 2nd messenger

13 7-Pass Receptor Interacting with Trimeric G-Protein

14 Formation of Cyclic AMP 2nd Messenger
Figures\Chapter15\High-Res\life7e-fig jpg

15 Phospholipid Derived 2nd Messengers

16 IP3 and DAG 2nd Messengers
phosphotidylinositol-4,5 - bisphosphate diacylglycerol Inositol-1,4,5-phosphate Figures\Chapter15\High-Res\life7e-fig jpg

17 Calcium Ions as a 2nd Messengers
Figures\Chapter15\High-Res\life7e-fig jpg

18 Nitric Oxide as a 2nd Messenger
Figures\Chapter15\High-Res\life7e-fig jpg

19 Signal Transduction Pathway Opens Ion Channels
Figures\Chapter15\High-Res\life7e-fig jpg

20 Signal Transduction Pathway Opens Ion Channels
Figures\Chapter15\High-Res\life7e-fig jpg

21 Signaling Cascades Alter Enzyme Activity
Figures\Chapter15\High-Res\life7e-fig jpg

22 Gap Junctions Connect Some Animal Cells
Figures\Chapter15\High-Res\life7e-fig jpg

23 Plasmodesmata Connect Some Plant Cells
Figures\Chapter15\High-Res\life7e-fig jpg


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