Term
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Definition
| the cell coat- formed from carbohydrate projections from the plasma membrane & mediates cell to cell and cell to substratum interactions |
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Term
| 7 The extracellular matrix (ECM) |
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Definition
| an organized network beyond the plasma membrane - plays role in stermining shape and activities of the cell |
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Term
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Definition
| ECM... a cont. sheet that underlies epithelial tissue and surrounds blood vessels. - maintian cell attchm. - substratum for cell migration - barrier to macromolecules |
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Term
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Definition
Fibrous gycoproteins found only in the ECM.
Most abundant protein in the body
provide high tensile strength
types of collagen speciffic to parts on the body
ALL COLLAGENS ARE A TRIMER OF POLYPEPTIDE CHAINS WOUND AROUND EACH OTHER
PROVIDE INSOLUABLE FRAMEWORK THAT DETERMINES MECHANICAL PROPERTIES OF THE MATRIX
disease: epidermolysis bullosa |
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Term
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Definition
protein polysaccharide complex, with the core protein attached to glycosaminoglycans (GAGs)
- have repeating disaccharide structure
-Neg charged gags attract cation which attracts water forming gel |
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Term
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Definition
a linear array of distinct polypeptides giving it a modular structure
-each polypeptide is about 30Fn modules
Fn modules are found in other proteins too
-FB HAS BINDING SITES FOR OTHER COMPONENTS OF THE ECM
-FB IS ONE COMPONENT THAT GUIDES MIGRATING CELLS DURING EMBRYOGENESIS |
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Term
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Definition
ECM
Extracellular glycoproteins consisting of three polypeptide cahins inked by disulfide bonds
-HELP CELL MIGRATION DURING DEVELOPMENT
-COMPONENTS OF BASEMENT MEMBRANES |
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Term
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Definition
| are proteins that contain oligosaccharide chains (glycans) covalently attached to polypeptide side-chains. |
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Term
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Definition
| are long carbohydrate molecules of monosaccharide units joined together by glycosidic bonds(binds carbohydrtes to another molecule). |
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Term
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Definition
family of membrane proteins composed of heterodimers with alpha beta subunits
-major role in integrating extracellular and intracellular environments/signals.
Role in ADHESION TO CELLS TO THEIR SUBSTRATUM OR OTHER CELLS
-linkage between integrins and their ligand mediates adhesion between cells and their enviroment
-binding of proteins to integrins is facilitated by tripeptde rgd
-integrins cytoplasmic domans contain binding sites for cytoplasmic proteins
-make connection between ECM and the cytoskeleton |
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Term
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Definition
scattered, discrete sites for CELL ADHESION TO THEIR SUBSTRATUM IN VITRO
-MAY ACT AS A SENSORY STRUCTURE
-ARE ALSO IMPLICATED IN CELL LOCOMOTION
*key proteins Actin, integrin |
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Term
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Definition
cell to surface BASAL ATTACHMENTS OF EPITHELIAL CELLS TO THE BASEMENT MEMBRANE IN VIVO
-contain a dense plaque with filaments consisting of keratin
-KERATIN FILAMENTS ARE LINKED TO THE ECM BY MEMBRANE-SPANNING INTEGRINS
*key proteins Keratin and integrin |
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Term
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Definition
disk shaped in cell to cell interaction
-**contain cadherins that link the two cells across a narrow gap
-** Cadherins of demosomes have different domain structures: desogleins and desmocollins
*keyproteins desoglein and desmocollin (cadherins) |
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Term
| 7 Focal Adhesions vs. Hemidemosomes |
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Definition
FA: outside of the cell in substrate in vitro
Inetgrins connect inner to outer cell surface
Actin filaments represent internal structures
HemiD: Outside of cell in substrate in vivo
Integrins connect inner to outter cell surface
Keratin filaments represent internal structures |
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Term
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Definition
FAMILY OF INTEGRAL MEMBRANEGLYCOPROTEINS THAT BIND TO SUGARS ON THE SURFACE OF THE CELLS
-contain a small cytoplasmic domain, a single membrane-spanning domain, and a large extracellular segment
Three types:
E-endothelial cells
P-on platlets and endothelial cells
L-on leukocytes |
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Term
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Definition
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Term
| 7 immunoglobin superfamily (IgSF) |
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Definition
most proteins are involved in immune functions.
-most igSF molecules mediate interaction of lymphocytes with cells required for immune response
-contain fibronectin like domains (FnIII) |
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Term
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Definition
glycoproteins tbat mediate ca2+ dependent cell-cell adhesion
-transmit signals from ECM to the cytoplasm
-mediate many of the changes in adhesive contacts during embryonic deleopment through the epithelial-mesenchymal transition (EMT) |
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Term
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Definition
| Migration from one location to another is associated with the loss if cadherin expression, allowing cadherin decficent cells to eliminate their connections with adjacent cells. and become neural tubes |
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Term
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Definition
- recruitment of leukocytes to site of injury
- NEUTROPHILS ATTAH P- and E-Selectins
-Neutrophils start to "roll" along wall of vessels |
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Term
| 7 The role of cell adhesion in inflammation |
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Definition
- as neutrophils interact with inflamed venule endotheliium, platelet activating factor (PAF) is displayed
-PAF sends a signal to invrease the binding activity of some integrins
-Activated integrins casue neutrophils to stop rolling and adhere firmly the wall of vessel |
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Term
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Definition
| The spread of a tumor to other parts of the body |
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Term
| 7 Mestastic cell properties |
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Definition
-are less adhesive
-able to penetrate several barriers
-able to invade normal tissues |
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Term
| 7 The role of cell adhesion in metastasis |
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Definition
DURING GROWTH AND DEVELOPMENT OF A TUMOR THERE IS LODD OF E-CADHERIN LEADING TO LESS ADHESION
-CHANGES IN NUMBERS AND TYPES OF CELL-ADHESION MOLECULES PROMOTE METATASIS |
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Term
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Definition
**form belts near apical surface called Junctional Complex
**cells of an adherens junction held together by calcium-dependent linkages (eg cadherins)
*Key proteins : actin, cadherins |
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Term
| 7 Transmembrane signaling |
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Definition
the transer of information across the plasma membrane
-** Integrins and cadherins can transmit signals from the extracellular environment to the cytoplasm |
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Term
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Definition
*specialized contacts between epithelial cells
-*located at the very apical end of the junctional complex between adjacent cells
-*serve as a barrier to the free diffusion of water and solutes from the extracellular compartment
-some are permeable to specffic ions or solutes
-form the blood-brain barrier
**keyproteins:occudin and claudin |
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Term
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Definition
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Term
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Definition
| form the major structural component of TJs and in the differnce in selective permaiblity |
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Term
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Definition
**sites between animal cells for intercellular communication
- composed entirely of the membrane protein connexin which are organized into a connexon
-gj intercellular communincation allows the passage of low-weight molecules
-**allow integration of activites of cells into a finctional unit
-**compatibility differences between connexins either promote or prevent communication between different cells
*key protein: connexin |
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Term
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Definition
provide plants protection against mechanical abrasion, pathogens, and osmotic stress
-the fibrous componet is cellulose
-cellulose is organized into microfibrils, (provide cell wall rigidity)
-matrix contans HEMICEEULOSES, PECTINS, and PROTEINS
-arrise as a ceel plate that forms between plasma membrane and daughter cells
-the walls of growing cells are PRIMARY WALLS and allow fexibility that the SECONDARY WALLS in mature cells lack |
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Term
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Definition
**cytoplasmic channels passing through cell walls of adjacent plant cells
-lined by plasma membrane
-contain a central structure (desmotuble)
-serve as sites of cell-cell communincation |
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Term
| 15 Extra cellular messenger molecules |
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Definition
| *transmit messages between cells |
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Term
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Definition
| the cell receptor is on its surface that respond to the messenger |
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Term
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Definition
| messenger molecules travel short distances through extracellular space |
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Term
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Definition
| messenger molecules reach their target cell through the blood stream |
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Term
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Definition
*Recieve the message
-some receptors generate an intracellular second messenger through an enzyme called an EFFECTOR.
-other surface receptors recruit proteins to their intracellular domains |
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Term
| 15 Signaling Pathways in signal transduction |
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Definition
consits of a series of proteins
- each protein in a pathway alters the conformation of the next protein
- protein conformation is usually altered by phosphorylation ( adding a phosphate group to another molecule)
-target proteins ultimately receive a message to alter cell activity |
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Term
| 15 extracellular messengers include... |
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Definition
-small molecules like amino acids and their derivatives
-gases such as NO and CO
-Eicosanoids,(lipids derived form fatty acids)
-peptides and proteins |
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Term
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Definition
- steroid hormone receptors (NR)
-**G-protein coupled recpetors (GPCRs)
-** Receptor protein-tyroine kinases RTKs
-ligand gated channels
-B and T receptors |
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Term
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Definition
| g prtoein coupled receptors are numerous and have seven trans-membrane domain and interact with G proteins |
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Term
| 15 Signal Transduction by G protein-coupled receptors |
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Definition
-Ligand binding on the extracellular domain changes the intracellular domain
-affinity for g proteins increases, and the receptor binds G protein intracellularly
-GDP is exchanged for GTP on the G protein, activating the G protein
-one ligand-bound receptor can activate many g proteins |
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Term
| 15 Termination of response in G protein couples receptors |
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Definition
-Densensitization- by blocking active receptors turning on additonal G proteins
-G protein couldped receeptor kinase GRK -activates a GPCR via phosphorylation
-proteins called arrestins compete with G proteins to bind GPCRs
-Termination of the response is accelerated by regulators of G protein signaling RGS |
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Term
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Definition
| target GPCRs and Gproteins |
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Term
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Definition
| is a 2nd messenger which amplify the response of the ligand |
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Term
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Definition
| activates protein kinase C which phosphorylates serine and threnine residues on target proteins |
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Term
| 15 phosphorylated phosphoinositides |
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Definition
form lipid-binding domains called PH domains
a derivative is Phosphoinositides (PI) |
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Term
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Definition
-one is calcium channel located at the surface of the smooth endoplasmic reticulum
-binding of ip3 opens the channel and allows ca2+ ions to diffuse out |
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Term
| 15 Regulation of blood glucose level |
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Definition
- **different stimuli acting on the same target may induce the same response
-** glucagon and epinephrine bind to different receptors on the same cell
-both hormones stimulate glucoses breakdown and inhibit synthesis
-**cAMP is activated by the G protein of both hormone receptors (convergence)
-Responses are amplified by signal cascades |
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Term
| 15 other aspects of cAMP signal Transduction |
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Definition
-some PKA molecules phosphorylate nuclear proteins
-phosphorlayted transcription facttors regulate gene expression
-phosphatases halt the reaction cascade
-cAMP is produced as long as the external stimuli is present |
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Term
| 15 role of GPCRs in sensory Preception |
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Definition
-rhodopsin is a photosensitive protein for black and white vision that is also a GPCRs
-sveral color recptors are GCPRs
-oderant receptors in the nose are gcprs
-taste receptors for bitter and sweet are gpcrs |
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Term
| 15 loss of function mutation |
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Definition
result in nonfunctional signal pathways
retinitis pigmentosa:lacks ability to activate g protein |
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Term
| 15 gain of function mutation |
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Definition
| creates a constituively activated G protein (bengin tumors,asthma blood pressure and hiv) |
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Term
| 15 Protein-tyrosine kinases |
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Definition
phosphorylate tyrosine residues on target proteins.
-regulate cell growth, division, differentiation, survival, and migration. |
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Term
| 15 receptor protein- tyrosine kinases (RTKs) |
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Definition
| cell surface receptors of the protein-tyrosine kinase family |
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Term
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Definition
-results from ligand binding
-protein kinase activity is activated
.tyrosine kinase phosphorylates another subunit of the receptor (autophosphorylation).
. RTKs phosphorylate tyrosines within phosphotyrosine motifs |
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Term
| 15 Phosphotyrosine-Dependent Protein-Protein Interactions |
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Definition
| **Phoosphorylated tyrosines bind effector proteins that have SH2 domains and PTB (Phosphotyrosine Binding) domains |
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Term
| 15 SH2 and PTB domain Proteins include |
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Definition
-adaptor proteins that bind other proteins
-docking proteins that supply receptors with other tyrosine phosphorylation sites
-signaling enzymes (kinases) that lead to changes in the cell
-transcription factors |
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Term
| 15 The Ras Map kinase pathway |
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Definition
-** ras Gprotein embedded in the membrane by a lipid group
-Ras is active when bound to gtp and inactive when bound to GDP
-ras can have GTPase activity |
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Term
| 15 Accesory proteins in ras-map kinase pathway |
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Definition
GAPs- shortenn the active time of Ras
GEFs-stimulate the exchange for GDp to GTP
GDIs-inhibit GDP |
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Term
| 15 Ras-MAP kinase cascade |
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Definition
| a cascade of enzymes resulting in activating transcription factors |
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Term
| 15 adapting map kinase to transmit different tyeps of information |
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Definition
-end results differ in different cells/ situations
-specificity of the MAP kinase response due to differences in the types of kinases participating and differences in spatial organization of components |
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Term
| 15 signaling by the the insulin receptor |
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Definition
-insulin regulates blood glucose levels by increasing cellular uptake of glucose
-The insulin receptor is a proteintyrsine kinase
.) autophosphorylated receptor is a protein-tyrosine kinase
.) IRSs bind proteins with SH2 domains, which activate downstream signal molecules.
.) SH2 domain-containg proteins are kinases that phosphorylate a lipid, PI3 kinase |
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Term
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Definition
-PKB regulates glucose uptake by GLUT4 transporters
.) GLUT4 transporters reside in intracellular membrane vesicales
.)Vesicles fuse with the mebrane in response to ligand binding to the IR
-Diabetes mellitus is caused by defects insulin signaling and type 2 diabetes is caused by gradual insensitivity to insulin |
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Term
| 15 Insulin signaling and lifespan |
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Definition
| - lifespan increased with insulin decreases; shows high levels and increased insulin sensitivity |
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Term
| Signaling pathways in Plants |
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Definition
-plants lack cyclic nucleotides and RTKs
-plants have protein kinases what phosphoylate histidine residues
>downstream cascade simlar to Map kinase cascade
>target of the cascade is usually transcription factors |
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Term
| Cytoplasmic calcium levels |
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Definition
are determined by events within a membrane
-calcium levels control cistol beacause it is pumped out into the extracellular space and the membrane is highly permeable to the ion
-calcium channels can be transiently opened by action potentiality or calcium itself
-**calcium binds to calcium binding proteins like calmodulin which afffects other proteins |
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Term
| Regulating calcium concentration in plant cells |
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Definition
-cytosolic calcium changes in response to sever stimuli, including light, pressure, gravity, and hormones
-Calcium signaling aids in decreasing turgor pressure in guard cells |
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Term
| Signaling pathways can converge, diverge, and cross talk as follows... |
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Definition
-**Signals form unrelated receptors can converge to activate a common effector
-**identical signals can diverage to activate a variety of effectors
-**signals can be passed back and forth between pathways as a result of crosstalk |
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Term
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Definition
| - GPCRs, receptors tyrosine kinases, and integrins bind to different ligands but they all can lead to a docking site for Gbr2 |
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