Epithelium: Cell Junctions Flashcards
Name the asymmetric junction(s)
Hemidesmosome (attach cells to the basal lamina)
Name the symmetric junction(s)
(btwn two cells) Tight Junction (occluding junction) Anchoring Junction ( belt desmosomes) Anchoring Junction ( spot desmosomes) Communicating Junction (Gap)
Tight Junction (occluding)
No intercellular space -circumferential belts at the apical domain of epthelial cells -links adjacent endothelial cells -regulate the passage of ions between adjacent epithelial cells -
Transcellular Pathway
Across the cell controlled by channels and receptors
Paracellular Pathway
Between the cells regulated by intracellular contact and CELL JUNCTIONS
Actin filaments are seen in what type of Junction
Tight
What is anchored to Zo-1 in Tight Junctions
Afadin-nectin complex JAMS
What type of dimers do Nectins form
cis-homodimers transhomodimers
JAMS (Junctional adhesion molecules) attach to
afadin and ZO-1
JAMS determine…
formation of cell polarity
Order of Junctions from the Lumen down
Tight (occluding) Zonula adherens (belt) Macula adherens (spot)
Tight Junctions ..what interacts with F-actin
occludin claudins JAMS
What components of the tight junction are seen in freeze fracture?
Occludin and Claudins
What type of junctions are show from top to bottom
Line 1
Line 2
Line 3
Tight Junction
Zonula adherens
Macula adherens
What type of Junction is this?
Tight Junction (freeze fracture) occludin and claudins
What type of Junction is #2
What is inside this intercellular space ?
Tight Junction
Occludin
Claudins
JAMS
Nectins
What type of Tight Junctions are part of the immunoglobin family of Cell Adhesion Moleculess?
Nectin and JAMS
Occludin and Claudin are part of what family of proteins?
Tetraspanins
What part of Tight Junctions are actin Linkers?
ZO
Tight Junctions separate which two domains?
Apical and Basolateral membrane domains
(prevent free diffusion of lipids and membrane proteins between them)
Tight Junctions regulate …
Paracellular Pathway of fluid and solutes (kidney blood filtration)
Nectin and JAMS form homodimers through what bonds
disulfide bonds
What type of filaments are associated with tight junctions?
Actin (microfilaments)
Freeze Fracture
Creates artifical (FACE)
Protoplasmic (wear bumps are seen) where occuludin and claudins seen
Extracellular face (where pits are seen)
results from spitting membrane across hydrophic core
uses heavy metals to coat the cell