Signal Transduction Pathway EXTRACELLULAR FLUID Plasma membrane CYTOPLASM Receptor Signaling molecule ligand Relay molecules in a signal transduction pathway Activation ID: 511772
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Slide1
Cell Signaling and TransductionSlide2
Signal Transduction Pathway
EXTRACELLULAR
FLUID
Plasma membrane
CYTOPLASM
Receptor
Signaling
molecule: ligand
Relay molecules in a signal transduction pathway
Activation
of cellular
response
TransductionAmplification of signal
Response
2
3
Reception
1Slide3
Protein Receptors in the Plasma Membrane
Most water-soluble signal molecules bind to specific sites on receptor proteins in the plasma membrane.
There are three main types of
membrane receptors
:G protein-coupled receptors
Receptor tyrosine kinasesIon channel receptors
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin CummingsSlide4
G-Protein Coupled ReceptorSlide5
Receptor Tyrosine KinaseSlide6
Signaling
molecule
(ligand)
Gate
closed
Ions
Ligand-gated
ion channel receptor
Plasma
membrane
Gate open
Cellular
response
Gate closed
3
2
1Slide7
Bozeman VideoSlide8
Transduction:
Cascades
of molecular interactions relay
signals from receptors to target molecules in the cell
Signal transduction usually involves multiple steps.
The molecules that relay a signal from receptor to response are mostly proteins.Multistep pathways can
amplify a signal: A few molecules can produce a large cellular response.Multistep pathways provide more opportunities for coordination and regulation of the cellular response.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin CummingsSlide9
Signaling molecule
Receptor
Activated relay
molecule
Inactive
protein kinase
1
Active
protein
kinase
1
Inactive
protein kinase2
ATP
ADP
Activeproteinkinase2
P
P
PP
Inactive
protein kinase
3
ATP
ADP
Active
protein
kinase
3
P
P
PP
i
ATP
ADP
P
Active
protein
PP
P
i
Inactive
protein
Cellular
response
Phosphorylation cascade
i
Amplification -- CascadeSlide10
Specificity
of
Cell Signaling
Signaling
molecule
Receptor
Relay
molecules
Response 1
Cell A. Pathway leads
to a single response.
Response 2
Response 3
Cell B. Pathway branches,leading to two responses.
Response 4
Response 5
Activation
or inhibition
Cell C. Cross-talk occurs
between two pathways.
Cell D. Different receptorleads to a different response.