Exam 3 Review

importance of cell adhesion

importance of cell adhesion

allow multicellular organisms to communicate with each other, which allows for organisms to develop specialized cell types, organs, and tissues

cell-adhesion molecules(CAMs)

membrane-bound proteins that adhere to either proteins in the membranes of other cells or molecules in the ECM

extracellular matrix (ECM)

meshwork of proteins and carbohydrates secreted by cells

main benefit of adhesion

it is dynamic, so cell-____ interactions vary in strength and reversibility, making them useful in different situations (e.g. extravasation, rolling, and arrest)

extravasion

mechanism where circulating cells can squeeze through endothelial cells, leaving the bloodstream and entering tissues

rolling

a weak, easily reversible adhesion that is mediated by CAMs called selectins

arrest

a strong adhesive interaction mediated by integrins that trigger extravasion

glycosaminoglycans (GAGs)

long polysaccharide chains with amino groups that are stiff, hydrophilic(stretched out for more exposure), and negatively charged and make the ECM gel-like

collagen

most common animal protein that form helical bundles that are very strong giving the ECM tensile strength

elastic fibers

hydrophobic segments between cross-links that give the ECM elasticity and resilience

fibronectin

glycoprotein that has domains that bind to other ECM proteins and to adhesion proteins in cell membrane ; it mediates attachment of CAMs to the ECM

tight junction

seals neighboring cells together and prevents leakage of molecules; MC: claudins, occludins; CA: actin filaments

adherens junction

joins an actin bundle in one cell to a similar one in a neighboring cell; MC: cadherins; CA: actin filaments

desmosome

joins intermediate filaments in one cell to those in a neighbor ;MC: cadherins; CA: intermediate filaments

gap junction

allows passage of small, water-soluble ions and molecules; MC: connexins

hemidesmosome

anchors intermediate filaments in a cell to the basal lamina; MC: integrins; CA: intermediate filaments

actin-linked cell-matrix junction

anchors actin filaments in cell to ECM; MC: integrins; CA: actin filaments

cadherins

calcium-dependent CAMs that form cell-cell adhesions between cells of the same type

integrins

transmembrane heterodimers that bind cells to the ECM; also participate in extravasion

quorum sensing

cell-cell communication that allows bacteria to share information about cell density and adjust gene expression accordingly

autocrine signaling

releasing signals that bind onto the same cell’s receptors

endocrine signaling

releasing signals, hormones, into the circulatory system (bloodstream)

paracrine signaling

releasing signals to a nearby cell

cell-to-cell contact

transmembrane proteins act as signaling molecules between cells

second messengers

transmit a signal from a receptor of a cell to a target within the cell (e.g. DAG+IP3, Ca2+, cAMP)

intermediate filaments

rope-like filaments with no polarity that help with cell shape and support (e.g keratin)

microfilaments

made up of actin monomers, and help with cell shape and support, cell movement, cytokinesis, vesicle transport and muscle contraction

microtubules

made of tubulin heterodimers and help with cell shape and support, mitotic spindle, and organelle arrangement

myosin

motor proteins associated with actin filaments

kinesin

motor proteins associated with microtubules; moves towards plus end

dynein

motor protein associated with microtubules; moves toward minus end