CAMs and Junctions Flashcards
Desmocollins and Desmogleins belong to which group of CAMs?
Cadherins
Zonula occludens and Desmosomes are associated with what type of CAM?
Cadherins
What serves as a major interface between the cadherins that hold adjacent cells together and their acting cytoskeletons?
Catenins
________ bind molecules in the ECM such as fibronectin and laminin
Integrins
__________ are molecular complexes that anchor cells together and reinforce the physical integrity of tissues and the cells that cells that make up the tissue
Zonula Adherens
_______ attach one cell to the ECM and are only associated with the basal domains
Hemidesmosomes
Selectins bind to ___________
carbohydrates
Fribronectin:
glycoprotein formed by two identical chains linked by disulfide linkages close to the c-terminal.
Two forms of fibronectin.
- Cellular fibronectin: from fibroblast, forms part of ECM
2. Plasma fibronectin: from hepatocytes, secreted into bloodstream.
Binding sites on fibronectin: (4)
heparing (proteoglycan), integrins, collagen, fibrin.
What are the types of calcium dependent CAMs?
cadherins, selectins
What are the two types of calcium independent CAMs?
Integrins, immunoglobulin superfamily molecules
Ligand recognized by cadherins
other cadherins (same or different, it don’t matter)
Ligand recognized by selectins
carbohydrates
Ligand recognized by integrins
extracellular matrix molecules
Ligand recognized by Ig superfamily
integrins
E-Cadherins (a classical cadherin) are found where?
Epithelial tissues
N-Cadherins (a classical Cadherin) are found where?
Nerve cells
P-Cadherins (a classical Cadherin) are found where?
Placenta.
Desmocollins and desmogleins (nonclassical cadherins) are found where?
Desmosomes (macula adherens)
_________ are the most common type of cadherins and have a __________ binding face.
- E-cadherins 2. HVA (form homophilic dimers)
A loss of __________, can be associated with invasive behavior of tumor cells.
e-cadherins
__________ are small proteins that link the cytoplasmic end of a cadherin with cytoplasmic actin
Catenins
Integrins have how many subunits?
Two
Name the Proteins (3) that can be used to connect integrin to actin filaments
Talin, Vinculin, Alpha-actinin
Give an example of intracellular tonofilaments
intermediate filaments such as keratin
in hemidesmosomes, __________ link the basal domains of cells vis the intracellular tonofilaments
Integrins
N-CAM
neural adhesion molecules.
I-cam-1 and I-cam-2
I-CAM-1 facilitates transendothelial migration of leukocytes
Adherens
are molecular complexes that anchor cell together and reinforce the physical integrity of tissues and the cells that make up the tissues.
Occludens
molecular complexes that establish and impermeable barrier between adjacent cells, especially epithelial cells, that prevents paracellular transport and maintains concentration differences btwn the environments on either site of the epithelial sheets.
Gap Junctions
composed of molecular pores that enable cells to rapidly exchange ions and small molecules that help coordinate activities among the cells that make up the tissue.
Types of Junctions: Zonula:
either adherens or occuldens variety, Zonula complexes travel all the way around the cell and link all neighboring cells to this central cell. (associated with intracellular actin)
Types of junctions: Macula:
“spot” or snap-like junction. Adherens variety and are often referred to as desmosomes (lateral domains of epithelial cells) or hemidesmosomes (basal domain of epithelial cells). Macula are associated with (tonofilaments) intermediate filaments)
Cadherin proteins are anchored to cytoplasmic plaques containing:
Desmoplakin, Plakoglobin
Zonula and macula adherens are mediated by interations with __________ and __________ cadherins
desmocollins, desmogleins
A hemidesmosome consist of
a cytoplasmic plate associated with intermediate filaments such as keratin. A membrance plaque linking it to the basement membrane.
Zonula occludens
are tight, belt-like occluding junctions. Provide a great barrier against the paracellular transport pathway. Other transmemebrane proteins include junctional adhesion molecules (JAMs) and Nectin.
Nectin:
is associated with the intracellular molecule, afadin
JAMs
are associated with both afadin and ZO-1
JAMs and Nectin:
are members of the immunoglobulin superfamily. stabilized by disulfide bonds and for cis-homodimers that facilitate cell adhesion.
Gap junctions are composed of _____________
Connexons
Each connexon, consist of __ __________, formaing a hexagonal structure with a ___________.
6 connexins, hollow center.
Gap junctions close when __________ ________ concentrations are high.
calcium Ion
