T14_CELLMEMBRANE
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<strong>T14</strong>:<br />
CELL MEMBRANES<br />
Natalia Ricco<br />
anricco@uic.es
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
1) INTRODUCTION
CELL MEMBRANES<br />
1) INTRODUCTION<br />
McKee, Bioquímica. 5ª edicion.<br />
★ Properties:<br />
• Hydrofobic core: impermeable barrier<br />
• diffusion of hydrophilic solutes<br />
• Transport modulated by proteins<br />
• Stability<br />
• Hydrofobic interactions<br />
• Membrane architechture maintained
CELL MEMBRANES<br />
1) INTRODUCTION<br />
McKee, Bioquímica. 5ª edicion.<br />
Keratynocyte<br />
Erythrocyte<br />
Deruy E, et al, PLoS ONE (2010)<br />
University of Michigan School of MEdicina
CELL MEMBRANES<br />
1) INTRODUCTION<br />
Alberts, Molecular Biology of the Cell. 4th edition.
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
2) FUNCTIONS<br />
Organization<br />
Molecule movement control. Communication!<br />
Growing<br />
Reproduction<br />
Adhesion<br />
Cell connection
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Amphipatic molecules:<br />
• Phosphoglycerides<br />
• Sphingolipids<br />
• Steroids<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
★ Sugars:<br />
• Glycocalyx
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Amphipatic molecules:<br />
• Phosphoglycerides<br />
• Sphingolipids<br />
• Steroids<br />
Triacylglycerol<br />
Plasmalogen
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Glycophorin A<br />
(Single-pass transmembrane protein)<br />
Lodish, Molecular Cell Biology. 5th edition.
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Voltage-gated Na channel<br />
(Multi-pass transmembrane protein)<br />
Namadurai et al., The Royal Society
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Fluoride channel<br />
(Multi-pass transmembrane protein)<br />
Stockbridge et al., Nature
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Porin<br />
(Membrane β barrel)<br />
Lodish, Molecular Cell Biology. 5th edition.
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Aquaporin<br />
(Multi-pass transmembrane protein)<br />
Freeman, Biología. 3ª edición.
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Lodish, Molecular Cell Biology. 5th edition.
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:<br />
• Integral membrane proteins<br />
• Lipid-anchored membrane protein<br />
• Periferal membrane proteins<br />
Lodish, Molecular Cell Biology. 5th edition.
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Proteins:
CELL MEMBRANES<br />
3) CHEMICAL COMPOSITION<br />
★ Sugars (Glycocalyx)<br />
• 5% of the outer monolayer<br />
• Some intracellular membranes<br />
• Most complex: gangliosides<br />
• Protection (ionic, mechanic and infectious)<br />
• Cell-Cell interaction markers (Selectin)<br />
Alberts, Molecular Biology of the Cell. 4th edition.<br />
Hempel et al., Trends in Molecular Medicine
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
4) TWO-DIMENSIONAL FLUID MODEL
CELL MEMBRANES<br />
4) TWO-DIMENSIONAL FLUID MODEL<br />
• Flip-flop: very rarely (once a month)<br />
• Within monolayer: 10 7 times/second<br />
• Individual lipid: rapid rotation around their<br />
axis<br />
Alberts, Molecular Biology of the Cell. 4th edition.
CELL MEMBRANES<br />
4) TWO-DIMENSIONAL FLUID MODEL<br />
ASSYMETRY<br />
★ Progressive familial<br />
intrahepatic cholestasis type I<br />
(Atp8B1, flippase)<br />
★Tangier disease (ABCA1,<br />
floppase) premature<br />
atherosclerosis<br />
★Scotts syndrome<br />
(coagulation)
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
5) PERMEABILITY<br />
• Hydorcarbonated chain length<br />
• Fluidity
CELL MEMBRANES<br />
5) PERMEABILITY<br />
• Hydorcarbonated chain length<br />
• Fluidity
CELL MEMBRANES<br />
5) PERMEABILITY<br />
• Hydorcarbonated chain length<br />
• Fluidity<br />
• Insaturations<br />
• Temperature<br />
• Cholesterol
CELL MEMBRANES<br />
5) PERMEABILITY<br />
• Hydorcarbonated chain length<br />
• Fluidity<br />
• Insaturations<br />
• Temperature<br />
• Cholesterol<br />
Temperature<br />
Increase fluidity & flexibility.<br />
Difficult to maintain shape.<br />
Temperature<br />
Decrease fluidity. Too rigid.<br />
Risk of break.
CELL MEMBRANES<br />
5) PERMEABILITY<br />
• Hydorcarbonated chain length<br />
• Fluidity<br />
• Insaturations<br />
• Temperature<br />
• Cholesterol
CELL MEMBRANES<br />
5) PERMEABILITY<br />
• Hydorcarbonated chain length<br />
• Fluidity<br />
• Insaturations<br />
• Temperature<br />
• Cholesterol<br />
Temperature<br />
Movement limitation<br />
Temperature<br />
Fluidity maintenance
CELL MEMBRANES<br />
5) PERMEABILITY
CELL MEMBRANES<br />
5) PERMEABILITY
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
6) LIPID RAFT<br />
• Aggregates of lipids & proteins<br />
• Heterogeneus in size (typically 50 nm)<br />
• Integrity maintained by cholesterol<br />
• Enriched for many types of cell-surface receptor proteins<br />
1. Non-raft membrane<br />
2. Lipid raft<br />
3. Lipid raft associated<br />
transmembrane protein<br />
4. Non-raft membrane<br />
protein<br />
5. Glycosylation<br />
modifications<br />
6. GPI-anchored protein<br />
7. Cholesterol<br />
8. Glycolipid
CELL MEMBRANES<br />
6) LIPID RAFT
CELL MEMBRANES<br />
1) Introduction<br />
2) Functions<br />
3) Chemical composition<br />
4) Two-dimensional fluid model<br />
5) Permeability<br />
6) Lipid Raft<br />
7) Transporters
CELL MEMBRANES<br />
7) TRANSPORTERS<br />
Simple diffusion vs Facilitated diffusion
CELL MEMBRANES<br />
7) TRANSPORTERS<br />
Facilitated diffusion
CELL MEMBRANES<br />
7) TRANSPORTERS<br />
Facilitated diffusion
CELL MEMBRANES<br />
7) TRANSPORTERS<br />
Passive transport: simple & facilitated diffusion (down the concentration<br />
gradient)
CELL MEMBRANES<br />
7) TRANSPORTERS<br />
Active transport (Pump)<br />
Sodium-potassium pump (Na + /K + ATPase)
CELL MEMBRANES<br />
7) TRANSPORTERS
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