Cell-Cell Interactions and Cell-Matrix Interactions Flashcards
Zonula occludens
tight seal between epithelial cells so that stuff from outside cannot come inside cell
apical side
runs throughout the entire cell
zonula adherens
connects actin filament bundle in one cell with that in the next cell
zips the cells closed
desmosome
connects intermediate filaments in one cell to those in the next cell
gap junction
allows passage of small water soluble molecules from cell to cell- cytosol within cell goes through the gap junction
focal junction
actin linked cell matrix adhesion anchors actin filaments in cell to extracellular matrix
hemidesmosome
anchros intermediate filaments in a cell to extracellular matrix
functions of cell adhesion molecules
structurally link the cell to the outside (other cell or matrix) and they are cell signaling complexes
other proteins can bind in cytoplasmic domain “plaque proteins” seen in structures like desmosomes
anchor protein
part of cytoplasmic domain of cell adhesive protein and link the adhesive molecule to cytoskeletal filament
cell adhesion molecules
cadherins, immunoglobulin family of CAMs, integrins
cadherins
proteins that span membrane; bind to other proteins on cell membrane
requires calcium
structural and signaling roles;
Actin binds to anchor protein, anchor protein binds to cadherin which traverses membrane and binds another cadherin which traverses membrane and binds to anchor porotein and then bind to actin in cytoskeleton
- structurally glued and one cell will respond to mechanical stress of another cell
proto-cadherins
link to eachother but not to cytoskeleton
IG type of CAM
found in nervous system, in synapses
integrins
alpha and beta subunit form a dimer which will bind to ECM
predominantly laminin or fibronectin (RGD domain);
bind to cytoskeleton
types of binding
homophilic- bind to identical proteins expressed by neighboring cell heterophilic- bind to proteins from same family but different genes
or
bind to extra cellular matrix
zonula occludens
linker transmembrane protein
claudin, occludin, JAM-1 (junctional adhesion molecule)
Zonula occludens intracellular plaque protein
ZO1, 2, 3
Zonula occludens filament
actin
ZOT
zonula occludens toxin
binds to receptor on surface of cell and is transported into cell by cell’s endocytotic mechanism
alter cellular signaling and lead to disassembly of zonula occludens
bacteria can invade host epithelia and increase movement of water into lumen of gut–> diarrhea
cholera is example
zonula adherens
fascia adherens
circles entire cell
larger distance between membranes- junction has cadherin which goes through membrane and binds to protein in cytoplasm;
provide structure and strength to tissue and barriers to movement between cells
zonula adherens linker transmembrane
cadherin
zonula adherens intracellular plaque protein
cell signaling: alpha, beta, gamma catenin; skeletal components: vinculin and alpha actinin
zonula adherens filament
actin
desmosomes
spot welds;
cadherin binding to plaque protein binding to keratin
macula adherens linker transmembrane
desmosome;
linker is cadherin (desmocollins and desmoglein)
macula adherens intracellular plaque protein
anchor proteins [plakophilin–plakoglobin (gamma-catenin)]–desmoplakin
macula adherens filament
intmdt filaments (keratin)
gap junctions
hole between cells allowing for free diffusion of ions
made up of six connexin proteins that form a hemi-pore on one membrane which will line up with hemipore on another membrane and form a pore
size of molecules which can pass through gap junctions
1400 daltons
ATP, calcium, small proteins, etc
hemidesmosome
spot weld at bottom of the cell that connects cell with extracellular matrix in the basal lamina
what proteins are targeted in Bullous pemphigoid?
BP180-membrane spanning complex
and BP230- attaches to keratin
linker transmembrane for hemidesmosome
integrins (alpha6 and beta4)
binds to laminin in ecm
intracellular plaque protein hemidesmosome
plectin, BP230
filament hemidesmosome
intermediate filament
focal adhesion
mechanical and signaling complex
linker transmembrane for focal adhesion
integrins
intracellular plaque protein for focal adhesion
talin, vinculin, alpha-actinin, FAK (focal adhesion kinase), src kinase, Ras, Raf, Grb2, SoS
filament for focal adhesion
actin
mechanical stress does what to focal adhesion
mechanical stress results in activation of kinases associated with focal adhesion–> activate MAP kinase pathway and signal nucleus to upregulate formation of adhesion and lead to actin meshwork formation
