This document summarizes recent research on lipid rafts and their role in cell signal transduction. Some key points:
1) Lipid rafts are small, dynamic assemblies of cholesterol and sphingolipids in the outer leaflet of the cell membrane that compartmentalize proteins and biochemical reactions.
2) Rafts can recruit certain proteins to initiate signaling cascades by exposing them to localized kinases, phosphatases, and other enzymes.
3) Caveolae are a subset of rafts that form flask-shaped invaginations involving caveolin proteins; they have roles in endocytosis, transcytosis, and calcium regulation.
4) Methods to study rafts are improving but challenging
Membrane proteins are proteins that interact with, or are part of, biological membranes. They include integral membrane proteins that are permanently anchored to the membrane and peripheral membrane proteins which are only temporarily attached to the lipid bilayer or to integral proteins.
Introduction
Definition
Chemical composition
Molecular Structure of PM
Bilayel Model
Garter and Grendel s Model
Overton e Model
Fluid Mosaic Model
. Membrane Protein
Transmembrane Protein
Exterinsic Protein
non cytosolic Protein
6. Protein complex in pm.( cell coat)
7. Function of PM
8. Referance
Membrane proteins are proteins that interact with, or are part of, biological membranes. They include integral membrane proteins that are permanently anchored to the membrane and peripheral membrane proteins which are only temporarily attached to the lipid bilayer or to integral proteins.
Introduction
Definition
Chemical composition
Molecular Structure of PM
Bilayel Model
Garter and Grendel s Model
Overton e Model
Fluid Mosaic Model
. Membrane Protein
Transmembrane Protein
Exterinsic Protein
non cytosolic Protein
6. Protein complex in pm.( cell coat)
7. Function of PM
8. Referance
The structure of the cell membrane, the phospholipid layer distinguished to the break down of protein and the lipid layer. Their structural components and the molecular basis of it.
The current model of cellular membranes is called PB and J sandwich.pdfbhim1213
The current model of cellular membranes is called PB and J sandwich molecular mosaic fluid
mosaic plasma membrane Which characteristic apply to the phospholipid membrane? It is
primarily a hydrophobic bilayer. Phospholipids are amphipathic Proteins are imbedded within
the phospholipids. The imbedded molecules can move freely within the membrane All are
important characteristics of the Cholesterol molecules in the membrane act to modulate
temperature dependent viscosity and fluidity of the membrane. moderate the effects of a high fat
diet promote fluidity in the membrane. allow for better membrane compaction and integrity.
allow transport across the membrane. One important feature of membranes in the
endomembrane system is that they can move freely from cell to cell. freely bleb off of and then
onto other components of this network. they contain small pieces of independently replicating
DNA. they move from the trans side of the membrane to the cis side. t
Solution
1. Fluid mosaic model.
Fluid mosaic model for plasma membrane proposed by Jonathan Singer and Garth Nicolson is
universally acceoted model for plasma membrane.
2. All are important characteristics.
Phospholipid molecules are hydrophobic and amphipathic. Which means that posess polar head
and non polar tails.
Some of the protien molecules are embedded in the phospholipid layer and these moelcules are
free to move due to fluid nature of plasma membrane.
3. Allows better membrane compaction and integrity.
Cholesterol is an amphipathic molecule like phospholipids. It contains a hydrophilic and a
hydrophobic portion. Cholesterol\'s hydroxyl (OH) group aligns with the phosphate heads of the
phospholipids. The remaining portion of it tucks into the fatty acid portion of the membrane.
Because of the way cholesterol is shaped, part of the steroid ring (the four hydrocarbon rings in
between the hydroxyl group and the hydrocarbon \"tail\") is closely attracted to part of the fatty
acid chain on the nearest phospholipid. This helps slightly immobilize the outer surface of the
membrane and make it less soluble to very small water-soluble molecules that could otherwise
pass through more easily.
4. They contain transport enzymes..
This presentation gives an overview of Lipid Rafts, how it was discovered, its importance and the future research in this area,Feel free to comment and ask any questions