CAMs Flashcards
list the 2 types of CAMs
calcium dependent or independent
list the 4 types of CAMs
Ca dep. = cadherins and selectins
Ca indep. = integrins and Ig superfamily
classical cadherins
- types = E, N, P
- homophilic
- bind to other cadherins via catenins
- actin filaments
- adheren junctions
nonclassical cadherins
- desmocollins and desmogleins
- homophilic
- intermediate filaments
- desmosomes
nonclassical cadherin cytoskeleton associations
the desmoplakin, plakoglobin and plakophilin
selectins
- P, E, L types
- heterophilic
- actin filaments
- bind to carbs
integrins
- heterophilic
- actin filaments
- immunological synapses and focal adhesions
hemidesmosomes bind to cytoskeleton components such as ?
laminin and fibronectin
classical cadherins are major components in _______ junctions
Ca mediated adheren junctions
classical cadherins form ____ and _____ _______ dimers.
cis and trans homophilic dimers
E-cadherins
epithelial tissues
N-cadherins
nervous tissues
P-cadherins
placenta tissue
nonclassical cadherins are found in ________ also called ______ .
desmosomes
macula adherens
differ between intra and extra cell domains of cadherins
interior domain is much more variable than exterior
intra are able to interact w/ different ligands and components to anchor cadherin to cytoskeleon
binding between cadherins is generally ______ .
homophilic
cadherin molecules of a specific subtype on one cell bind to other molecules of ________ on adjacent cells.
molecules of same kind on adjacent cells
thus the spacing between membranes is precisely defined since they are same molecules w/ same bond lengths
the homophilic binding occurs at the _______ tips of cadherin molecules
N-terminal
the protein chains of cadherins form …..
terminal knot and nearby pocket
adjacent cadherin binds by inserting it’s knob into the pocket of the other
role of Ca in cadherin-mediated adhesion
Ca binds to sites near hinges of each bead so that it is rigid and rod like
if Ca is removed whole thing will be flexible/floppy
causing cadherins to be degraded
bond w/ neighbor cells lost
cadherins bind to their partners w/ _____ affinity.
low
thus strong attachments are achieved by many parallel bonds working together
functioning like velcro
cadherin adhesion is _______ but can easily be ______ .
group strength is strong
but easily disassembled
cadherin dependent homophilic adhesions mediate highly _____ recognition, thus enabling cells to ?
selective
similar cells to stick together and segregate from other types of cells
thus cell “sorting out”
what are the most common type of cadherins?
E-cadherins
form dimers via HVA binding face
HVA binding face
histidine-valine-alanine seq.
found on E-cadherins, at tip of extra cell end of cadherin molecule
catenin purpose
major interface between cadherins and the actin cytoskeleton of the cells being held together
catenin
–small proteins that link cytoplasmic end of a cadherin w/ cytoplasmic actin
B and y catenins
- -attach to cytoplasmic end of cadherin
- -b attaches to a catenin
a catenin
binds to cytoplasmic actin and b catenin
thus connecting the cadherin to actin cytoskeleton
selectins bind _____, thus belong to the ______ .
carbs
lectin group