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Fig. 11-1 Figure 11.1 How do the effects of Viagra (multicolored) result from its inhibition of a signaling-pathway enzyme (purple)?

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Presentation on theme: "Fig. 11-1 Figure 11.1 How do the effects of Viagra (multicolored) result from its inhibition of a signaling-pathway enzyme (purple)?"— Presentation transcript:

1 Fig. 11-1 Figure 11.1 How do the effects of Viagra (multicolored) result from its inhibition of a signaling-pathway enzyme (purple)?

2 Yeast cell, mating type a Yeast cell, mating type 
Fig. 11-2  factor Receptor 1 Exchange of mating factors a a factor Yeast cell, mating type a Yeast cell, mating type  2 Mating a Figure 11.2 Communication between mating yeast cells New a/ cell a/ 3

3 1 Individual rod- shaped cells 2 Aggregation in process 3
Fig. 11-3 1 Individual rod- shaped cells 2 Aggregation in process 0.5 mm 3 Spore-forming structure (fruiting body) Figure 11.3 Communication among bacteria Fruiting bodies

4 Gap junctions between animal cells Plasmodesmata between plant cells
Fig. 11-4 Plasma membranes Gap junctions between animal cells Plasmodesmata between plant cells (a) Cell junctions Figure 11.4 Communication by direct contact between cells (b) Cell-cell recognition

5 Figure 11.5 Local and long-distance cell communication in animals
Local signaling Long-distance signaling Target cell Electrical signal along nerve cell triggers release of neurotransmitter Endocrine cell Blood vessel Neurotransmitter diffuses across synapse Secreting cell Secretory vesicle Hormone travels in bloodstream to target cells Local regulator diffuses through extracellular fluid Target cell is stimulated Target cell Figure 11.5 Local and long-distance cell communication in animals (a) Paracrine signaling (b) Synaptic signaling (c) Hormonal signaling

6 Plasma membrane 1 Reception Transduction Response Receptor Activation
Fig EXTRACELLULAR FLUID CYTOPLASM Plasma membrane 1 Reception 2 Transduction 3 Response Receptor Activation of cellular response Relay molecules in a signal transduction pathway Figure 11.6 Overview of cell signaling Signaling molecule

7 Signaling-molecule binding site
Fig. 11-7a Signaling-molecule binding site Figure 11.7 Membrane receptors—G protein-coupled receptors, part 1 Segment that interacts with G proteins G protein-coupled receptor

8 Figure 11.7 Membrane receptors—G protein-coupled receptors, part 2
Fig. 11-7b Plasma membrane G protein-coupled receptor Inactive enzyme Activated receptor Signaling molecule GDP G protein (inactive) Enzyme GDP GTP CYTOPLASM 1 2 Activated enzyme Figure 11.7 Membrane receptors—G protein-coupled receptors, part 2 GTP GDP P i Cellular response 3 4

9 Fully activated receptor tyrosine kinase
Fig. 11-7c Signaling molecule (ligand) Ligand-binding site Signaling molecule  Helix Tyr Tyr Tyrosines Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Tyr Receptor tyrosine kinase proteins Dimer CYTOPLASM 1 2 Activated relay proteins Figure 11.7 Membrane receptors—receptor tyrosine kinases Cellular response 1 Tyr Tyr P Tyr Tyr P Tyr Tyr P P Tyr Tyr P Tyr Tyr P Tyr Tyr P P Cellular response 2 Tyr Tyr P Tyr Tyr P Tyr P Tyr P 6 ATP 6 ADP Activated tyrosine kinase regions Fully activated receptor tyrosine kinase Inactive relay proteins 3 4

10 1 Signaling molecule (ligand) Gate closed Ions Plasma membrane
Fig. 11-7d 1 Signaling molecule (ligand) Gate closed Ions Plasma membrane Ligand-gated ion channel receptor 2 Gate open Cellular response Figure 11.7 Membrane receptors—ion channel receptors 3 Gate closed

11 Hormone (testosterone) Plasma membrane Receptor protein Hormone-
Fig Hormone (testosterone) EXTRACELLULAR FLUID Plasma membrane Receptor protein Hormone- receptor complex DNA Figure 11.8 Steroid hormone interacting with an intracellular receptor mRNA NUCLEUS New protein CYTOPLASM

12 Phosphorylation cascade
Fig. 11-9 Signaling molecule Receptor Activated relay molecule Inactive protein kinase 1 Active protein kinase 1 Inactive protein kinase 2 ATP Phosphorylation cascade ADP Active protein kinase 2 P PP P i Figure 11.9 A phosphorylation cascade Inactive protein kinase 3 ATP ADP Active protein kinase 3 P PP P i Inactive protein ATP ADP P Active protein Cellular response PP P i

13 Fig. 11-10 Figure 11.10 Cyclic AMP Adenylyl cyclase Phosphodiesterase
Pyrophosphate P P i ATP cAMP AMP Figure Cyclic AMP

14 First messenger Adenylyl cyclase G protein GTP G protein-coupled
Fig First messenger Adenylyl cyclase G protein G protein-coupled receptor GTP ATP Second messenger cAMP Figure cAMP as second messenger in a G-protein-signaling pathway Protein kinase A Cellular responses

15 EXTRACELLULAR FLUID Plasma membrane Ca2+ pump ATP Mitochondrion
Fig EXTRACELLULAR FLUID Plasma membrane Ca2+ pump ATP Mitochondrion Nucleus CYTOSOL Ca2+ pump Endoplasmic reticulum (ER) Figure The maintenance of calcium ion concentrations in an animal cell Ca2+ pump ATP Key High [Ca2+] Low [Ca2+]

16 EXTRA- CELLULAR FLUID Signaling molecule (first messenger) G protein
Fig EXTRA- CELLULAR FLUID Signaling molecule (first messenger) G protein DAG GTP G protein-coupled receptor PIP2 Phospholipase C IP3 (second messenger) IP3-gated calcium channel Figure Calcium and IP3 in signaling pathways Endoplasmic reticulum (ER) Various proteins activated Cellular responses Ca2+ Ca2+ (second messenger) CYTOSOL

17 Growth factor Reception Receptor Phosphorylation cascade Transduction
Fig Growth factor Reception Receptor Phosphorylation cascade Transduction CYTOPLASM Inactive transcription factor Active transcription factor Figure Nuclear responses to a signal: the activation of a specific gene by a growth factor Response P DNA Gene NUCLEUS mRNA

18 Glucose-1-phosphate (108 molecules)
Fig Reception Binding of epinephrine to G protein-coupled receptor (1 molecule) Transduction Inactive G protein Active G protein (102 molecules) Inactive adenylyl cyclase Active adenylyl cyclase (102) ATP Cyclic AMP (104) Inactive protein kinase A Active protein kinase A (104) Figure Cytoplasmic response to a signal: the stimulation of glycogen breakdown by epinephrine Inactive phosphorylase kinase Active phosphorylase kinase (105) Inactive glycogen phosphorylase Active glycogen phosphorylase (106) Response Glycogen Glucose-1-phosphate (108 molecules)

19 Fig. 11-17 Figure 11.17 The specificity of cell signaling Signaling
molecule Receptor Relay molecules Response 1 Response 2 Response 3 Cell A. Pathway leads to a single response. Cell B. Pathway branches, leading to two responses. Figure The specificity of cell signaling Activation or inhibition Response 4 Response 5 Cell C. Cross-talk occurs between two pathways. Cell D. Different receptor leads to a different response.

20 Signaling Plasma molecule membrane Receptor Three different protein
Fig Signaling molecule Plasma membrane Receptor Three different protein kinases Figure A scaffolding protein Scaffolding protein

21 Fig Figure Apoptosis of human white blood cells 2 µm

22 Figure 11.20 Molecular basis of apoptosis in C. elegans
Ced-9 protein (active) inhibits Ced-4 activity Mitochondrion Ced-4 Ced-3 Receptor for death- signaling molecule Inactive proteins (a) No death signal Ced-9 (inactive) Cell forms blebs Death- signaling molecule Figure Molecular basis of apoptosis in C. elegans Active Ced-4 Active Ced-3 Other proteases Nucleases Activation cascade (b) Death signal

23 Interdigital tissue 1 mm Fig. 11-21
Figure Effect of apoptosis during paw development in the mouse

24 Reception Transduction Response Receptor Activation of cellular
Fig. 11-UN1 1 Reception 2 Transduction 3 Response Receptor Activation of cellular response Relay molecules Signaling molecule

25 Fig. 11-UN2

26 You should now be able to:
Describe the nature of a ligand-receptor interaction and state how such interactions initiate a signal-transduction system Compare and contrast G protein-coupled receptors, tyrosine kinase receptors, and ligand-gated ion channels List two advantages of a multistep pathway in the transduction stage of cell signaling Explain how an original signal molecule can produce a cellular response when it may not even enter the target cell Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

27 Define the term second messenger; briefly describe the role of these molecules in signaling pathways
Explain why different types of cells may respond differently to the same signal molecule Describe the role of apoptosis in normal development and degenerative disease in vertebrates Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings


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