Term
| What is the junctional complex? |
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Definition
| Junctional Complex is composed of tight junction, adhesion belt, & desmosome |
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Term
| Components of the adhesion belt |
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Definition
Transmembrane protein
§ Junctional plaque protein serves as intermediate protein allowing the cytoskeletal protein to attach
§ Actin |
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Term
| Structure of the ZO aka tight junction |
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Definition
quilt
-Consists of two FUSED plasma membranes. Proteins from each cell mem. Fuse with each other forming a belt structure
-2 types of proteins, combo determines how tight the jxn is:
1. transmembrane: occludin, claudin 2. cytoskeleton: actin (attach to protein) |
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Term
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Definition
-“Gate”: diffusion barrier for paracellular tranport
-“Fence”: maintains asymmetry in protein & lipid comp b/t apical & basolateral surfaces - like plastic of a 6-pack |
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Term
| Importance of ZO for polarity |
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Definition
| Asymmetry of cells is very important for maintenance of cell polarity (ie. Na/K pump). Some tight junctions are leaky to permit substances to leak out |
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Term
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Definition
- a belt that joins the cells
plaque proteins are vinculin and catenins.
linker proteins are E-cadherins
cytoskeletal proteins are actin |
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Term
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Definition
Maintain cell-cell stability
-Possibly involved in the formation of an epithelial tube
-Possibly involved in signal transduction
-help maintain seal from intercellular space
-also like plastic of a 6-pack |
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Term
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Definition
they are between the cell matrix and basement membrane and adhere cells to their "mattress"
linker protein is integrin |
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Term
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Definition
2 dense plaques (attachmt proteins) on the cytoplasmic surfaces of two adjoining cells.
-Transmembrane linker protein (cadherins, fingers)
–they are Ca2+ dependent proteins
-Intermediate filaments insert into plaque.
-Desmosomes link filament to cell & creating stability. The gap between the cells are filled with dense fibrilar proteins |
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Term
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Definition
-Plaque protein = desmoplakins
-Fibrilar proteins=desmogliens & desmocollins
-spot jxn
- Cytoskeletal Protein = intermediate filaments (Tonofibrils=cytokeratin) |
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Term
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Definition
| Maintain stability and strength between cells or between cells or b/t cell and ECM |
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Term
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Definition
between cells and connective tissue
basal region of the cell
half of a desmosome
ex- cornea |
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Term
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Definition
| Various locations on the lateral surface of cell |
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Term
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Definition
Consists of fused connexons from each cell to create a pore through which cell messages (ions/proteins/enzymes) can be passed
1 gap jxn = 2 connexon , joined head-to-head, each connexon= 6 connexins subunits
several subtypes of connexins, gap junctions don't have to be homogenous |
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Term
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Definition
Cell-to-cell communication
-allow passage of molecules <1000 kD
-twists shut when high Ca2+/low pH |
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Term
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Definition
| Its a trasmembrane linker glycoprotein found in tight junctions aka Zonula Occludens |
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Term
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Definition
transmembrane linker glycoprotein found in ZA
Mediates intercellular binding
Most common:
N-cadherin: neuro cell E-cadherin: epithelial cell |
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Term
| Desmogleins and Desmocollins |
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Definition
| transmembrane linker glycoprotein found on desmosomes |
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Term
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Definition
transmembrane linker glycoprotein found in focal contacts and hemidesmosomes
Intracellular proteins attach integrin to cytoskeleton
Extracellular proteins (laminin/firbonectin) attach integrin to collagen fibers |
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Term
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Definition
junctional plaque proteins found in ZA
one side attaches to the cytoskeleton and the other to side to adherens |
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Term
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Definition
junctional plaque protein found in focal contacts
one side attaches to the cytoskeleton and the other to side to adherens |
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Term
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Definition
junctional plaque protein found in desmosomes
one side attaches to the cytoskeleton and the other to side to adherens |
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Term
| role of actin filaments in junctions |
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Definition
it is a cytoskeletal protein found in ZA and ZO
its forms bundles |
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Term
| Role of keratin in cell adhesion |
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Definition
| it is a cytoskeletal protein found in desmosomes and hemidesmosomes |
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Term
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Definition
| is an autoimmune skin disease where body produces antibodies to break down its own desmosomes |
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