Lecture 2--membranes

Studying proteins of the plasma membrane solubilize

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Unformatted text preview: olubilize the membrane and run proteins on a gel Studying proteins of the plasma membrane Add trypsin to digest proteins on outside of cell Studying proteins of the plasma membrane Permeabilize and add trypsin to digest proteins on inside and outside of cell Studying proteins of the plasma membrane Membranes contain many associated proteins and carbohydrates Singer and Nicolson model most proteins are more than one thing Functions of Membrane Proteins channels or pumps that actively allow things to moe fro one s ide to other perceive signals from outside and transduce s ignal attach to extracellular matrix or exoskeleton inside cell protmote adhesion image from Nature Education website Functions of Plasma Membrane Proteins Receptors Signal Receptors recognize specific signals from the outside to promote transcription, proliferation, survival, death, changes in cell shape, migration, etc Functions of Plasma Membrane Proteins Attachment Receptors on the surface of cells can be used to attach to the extracellular matrix or to other cells Example: Receptors mediate recruitment of leukocytes to inflammatorythe body by moving thorugh blood vessels leukkocytes patrolling sites when they find the infection they have to find their way out the blood vessel wall; need to respond to only specific signals, to do that, they roll wround slowly on the walls of blood vessels. they have to attach, and detach over and over from blood vessles. that means that tey ahve to attche waeakly to the blood vessels, use e-selectin ligand (protein) that attaches to a protein on the v essel called eselctin, have weak interaction that allows the immune cell to attach and deattch over and over easily blood vessel lumen immune cell blood vessel wall endothelial c ell, type of pithelial cell Immune blood cells roll along the inner surface of blood cells via a specific interaction between a signal on their surface and the E-selectin receptor on vascular cells blood vessel lumen Example: Receptors mediate recruitment of leukocytes to inflammatory sites IL-8 and ICAM-1 attaches s trongly to eachother A chemokine secreted at sites of infection is sensed by the IL-8 receptor on immune cells, causing them to express integrin receptors that bind tightly to ICAM-1 on vascular cells blood vessel lumen Example: Receptors mediate recruitment of leukocytes to inflammatory sites showing importance of signaling proteins Tightly bound immune cells can squeeze between vascular cells to access the infection site Functions of Plasma Membrane Proteins Transport oxygen can diffuse directly thorugh membrane, tohers need channels Regulation of Glucose Uptake in Muscle and Fat Cells by Insulin glcone small molecule that need s to be transported to cells inorder to be broken down to make ATP when body need sugar to make ATP, body releases insulin, that goes through blood s tream, the insulin receptor an sense when insulin is there, Activation of the insulin receptor leads to mobilization of glucose transporter, allowing import of glucose Regulation of Glucose Uptake in Muscle and Fat Cells by Insulin vesicles with glut 4 then fuse to plasma membrane, s ignal transdution cascade which leads to the diffusion of the vesicle to the plasma membrane, and glucose can come in the cell. Activation of the insulin receptor leads to mobilization of glucose transporter,...
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This note was uploaded on 02/23/2014 for the course MCDB 165A taught by Professor Iruela-arispe during the Winter '08 term at UCLA.

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