Lipid bilayer
Draw Neuron L1 , page 14
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Membrane proteins
Voltage gated Na+ channel
- Allows …. to enter
- Gated = …. or …. by a specific signal (signal change in voltage)
- Allows …. movement, rapid
- Essential for …. ….
Membrane proteins
Voltage gated Na+ channel
- Allows NA+ to enter
- Gated = OPENED or CLOSED by a specific signal (signal change in voltage)
- Allows SELECTIVE movement, rapid
- Essential for ACTION POTENTIAL
Why is a channel or membrane protein important
- Essential for …
- Proteins give ….
- Important in …../…..
- ….. poisons
Why is a channel or membrane protein important
- Essential for FUNCTION
- Proteins give SPECIFICITY
- Important in DYSFUNCTION / DISEASE
- TOXIC poisons
……
- Scaffolding protein
- Proximal axon
- Nodes
……
- Transmembrane protein
- Member of neurexin family
- Cell adhesion
…….
- Microtubule associated protein
- Absent in most astrocytes
ankG
- Scaffolding protein
- Proximal axon
- Nodes
Caspr
- Transmembrane protein
- Member of neurexin family
- Cell adhesion
MAP2
- Microtubule associated protein
- Absent in most astrocytes
Immunohistochemistry - general method
Rat - protein of .... (antigen) > ..... Antibody (made in a goat) > .... Antibody (Antibody to the species goat)
Neurons L1, Page 20
Immunohistochemistry - general method
Rat - protein of INTEREST (antigen)
>
PRIMARY ANTIBODY Antibody (made in a goat)
>
SECONDARY Antibody (Antibody to the species goat)
Myelinated axon
Red = … …..
green = ….. (paranodal protein)
Myelinated axon
Red = VNa+ channels
green = Caspr (paranodal protein)
Chemical Synapse
Presynaptic
- …. ….
- Active zones - neurotransmitter release
Cleft
- Matrix fibrous ….
Postsynaptic
- ….. …..
- Receptors for neurotransmitters
Concept: the synapse is membrane specialization = … ….
Chemical Synapse
Presynaptic
- SPECIALIZED MEMBRANE
- Active zones - neurotransmitter release
Cleft
- Matrix fibrous PROTEINS
Postsynaptic
- SPECIALIZED MEMBRANE
- Receptors for neurotransmitters
Concept: the synapse is membrane specialization = MEMBRANE PROTEINS
….. receptor - transmitter gated ion channel
… …. - post synaptic density
… - Scaffold protein, under the plasma membrane for the clustering of receptors, ion channels etc
draw NL1, page 26
NMDA receptor - transmitter gated ion channel
COMPLEX PROTEIN - post synaptic density
PSD-95 - Scaffold protein, under the plasma membrane for the clustering of receptors, ion channels etc
Cleft
- … matrix
- Mind the gap (MTG) - … protein secreted ……
- Cell adhesion molecules - interact with molecule on …. of adjacent cell
Cleft
- TRANS-SYNAPTIC matrix
- Mind the gap (MTG) - BINDING protein secreted PRESYNAPTICALLY
- Cell adhesion molecules - interact with molecule on SURFACE of adjacent cell
NL1, PAGE 31 & 32
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Recap
NL2, page 2
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L2 objectives
With respect to the cytoskeleton of a neuron you should be able to;
- List the three main cyto-skeletal filaments and describe their basic structure
The importance of cytoskeleton in the function of neurons
- Describe the functional roles of each cytoskeletal element
- How to investigate the cytoskeleton
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Microtubules
- …nm diameter
- Hollow tube of protein …..
- Made of …..
- A …. molecule
- Add tubulin dimers at … end to ….
- …… - de- or re-polymerize as needed
Microtubule associated proteins (…)
- MAP-2 in … & ….
- Tau in … & ….
Microtubules
- 20-28nm diameter
- Hollow tube of protein TUBULIN (13)
- Made of DIMERS
- A POLARIZED molecule
- Add tubulin dimers at + end to ELONGATE
- LABILE - de- or re-polymerize as needed
Microtubule associated proteins (MAPs)
- MAP-2 in SOMA & DENDRITE
- Tau in DENDRITE & AXON
Microtubules and MAPs
L2, page 9
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Perikarya (soma) and dendrites of neurons are strongly and specifically stained with the ….
Cell nuclei are visualized with …. …. stain
Perikarya (soma) and dendrites of neurons are strongly and specifically stained with the MAP2
Cell nuclei are visualized with DAPI DNA stain
rat hippocampus neurons with anti-Tau are coloured …
Mouse anti-MAP 2 (only dendrite) Are coloured …
rat hippocampus neurons with anti-Tau are coloured RED
Mouse anti-MAP 2 (only dendrite) Are coloured GREEN
Revision
L2, page 14
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Draw a motor protein
L2, page 15
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More proteins
L2, page 16
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Neurofilaments
…nm diameter
- …. cytoskeletal component
- = …. ….
- Huge …. strength
- Most … of cytoskeletons
- Important in … ….
- Have … ….
Neurofilaments
10nm diameter
- PREDOMINANT cytoskeletal component
- = INTERMEDIATE FILAMENTS
- Huge MECHANICAL strength
- Most STABLE of cytoskeletons
- Important in STRUCTURAL FRAMEWORK
- Have ASSOCIATED PROTEINS
Microfilaments
Actin - …. (G) & …. (F)
- …. nm
- Dynamic = remodelling of actin filaments ….
Microfilaments
Actin - MONOMERIC (G) & FILAMENTOUS (F)
- 3-5 nm
- Dynamic = remodelling of actin filaments CONTINUALLY
In a microfilament get net flow of newly acquired G-actin through the filament = known as actin ….., -> a dynamic turnover of actin filaments while filament length is maintained
In a microfilament get net flow of newly acquired G-actin through the filament = known as actin TREADMILLING, -> a dynamic turnover of actin filaments while filament length is maintained
actin in the post synaptic terminal
L2, page 23
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Actin in the presynaptic terminal
L2, page 24
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