quiz 3 stuff Flashcards
PAR complex
PAR3, PAR6, aPKC, Cdc42
Crumbs complex
CRB, PALS1, PATJ
Scrib complex
SCRIB, LGL, DLG
LGL
cytoskeletal protein, can bind myosin II
DLG
Scaffold protein
ER seperation
continuous w/ nuclear membrane, segregates during interphase
Mitochondria seperation
evenly distribute during segregation, localizes to cleavage furrow (likely supplies energy)
Golgi
-fragments during M phase, move w/spindle poles, reconstruct in telophase
-in cell plates in plants
cellular fusion occurs in
muscle cells
steps of cellular fusion
embroynic progenitors –> proliferating myoblasts –> differentiating myocytes –> postmitotic myotube (functional unit of skeletal muscle)
decision to divide symmetrically or not is partially decided by
RNA localization
asymmetric divison (RNA process)
proteins (P bodies) carrying RNA move them to one side of dividing cell –> RNA molecules code for proteins, can carry out different functions compared to other cell
mitosis without cytokines (nuclear division) results in
large cell w/ several thousand nuclei
Taxol
prevents MT depolymerization, cant break asters
midbody
acts as a landmark, gives orientation to create polarized structure
direction of neuronal comunication
from dendritic terminal, through soma and out through axonal terminal
axon composition
long and thin, uniform width, branches at right angles from cell body
dendrite composition
short (get thinner the further from cell body it goes), unergoes y shaped branching
spacing between MT in axon vs dendrites
tau in axon forms loops - spacing between MTs is smaller in axon than dendrites
Golgi extends into ______ but not ________
dendrites, axon
since there is no golgi in the axon, proteins must be stored/modified (N-glycosylated) in the ________ and transported to the ___________
soma, axonal terminal
anterograde transport
away from golgi
retrograde transport
towards golgi
MTs are oriented relative to
golgi
anterograde transport is to which end and transported by which motor protein
+ end, kinesin
retrograde transport is to which end and transported by which motor protein
- end, dynein
nocadazol (NDZ) causes
MTs to depolymerize
in axon, minus end is oriented towards ________ and plus end is oriented towards _________
soma, axon terminus
what direction does transport occur in in dendrites
both directions, has golgi everywhere
Action potential depolarization and repolarization
Depol: Na+ channel open, Na+ moves into axon
Repol: K+ channel open, K+ moves out of axon
_________ drives plasma membrane protrusion
actin polymerization
leading edge portrusion results from
myosin contraction at the rear, pushes PM forward
filopodia
common in migrating growth cones of neurons and fibroblasts - 1 dimensional - long bundles of parallel actin
lamellipodia
common in epi cells, neurons and fibroblasts - 2 dimensional - mesh-like network of branched actin
invadopodia
3-dimensional actin-rich protrusions that penetrate tissue barriers
cell movement begins with
lamellipodia
do MTS penetrate lamellipodia actin netword
no
filopodia are thought to act as cellular
antennae - probe microenvironment, have receptors to respond to surrounding environment
filopodia are also involved in
cell-cell adhesions, guiding growing dendrites to chemoattractants
growth cone composition
lamellipodia w finger like projections (filopodia) coming off of it, MTs hang back while filopodia explores environ.
what is critical for wound healing in epi cells
lamellipodia
cofilin
disassembles actin filaments - at rear of lamellipodia
ARP 2/3
machinery for migration is dependant on this
-facilitates nucleation of new actin polymers at 70 degree angle to the existing actin polymers
invadopodia begins with
localized loss of actin cortex (relaxation)
blebs form when
PM detaches from cytoskeleton or underlying actin cortex
what allows membrane to protrude (blebbing)
contraction of myosin w/o actin cortex
what promotes focal adhesion formation
actin polymerization force added to myosin contraction
what moves cell forward
myosin contraction and cell adhesion coupled with de-adhesion at rear
premature loss of focal adhesions
actin filaments slip back away from leading edge following actin polymerization
Cell polarity is caused by
Members of the Rho family (Cdc, Rac, Rho)
Cdc42 activation on ________
inner surface of PM
Cdc42 activation triggers
-filopodia formation
-actin polymerization and bundling
Cdc42 filopodia formation
Cdc42 –> WASp –> mDia (profilin) (and ARP2/3 in lamellipodia but mainly profilin) –> filamentous actin
Rho myosin contraction
Rho –> ROCK –> pMLC –> Myosin II contraction
Rac1 lamellipodia formation
Rac1 –> WASp –> ARP2/3 –> Actin mesh
What happens when Rho dominates
Actin-myosin contraction
What happens when Rac dominates
Polymerization (protrusion)
chemotaxis
chemotactic signals can promote cell migration toward or away from a signal
chemotaxis signal cascade
chemoattractant –> GCPR on migrating cell–> PI3K –> RAC –> ARP2/3 –> lamellipodia formation
PI3K rapidly degraded - cannot diffuse far giving directionality to new formed lamellipodia
GCPR –> myosin contraction –>
Rac in lead, Rho in rear gives polarity to signal cascade
Neutrophil chemotaxis assay
Release of a N-formylated peptides from a pipette
tip promotes lamellipodia formation and the rapid
migration of neutrophils toward the pipette
6 general external signals
- ECM adhesion
- proteins in matrix growth cone can associate w and grow along - Cell surface adhesion
- protein present on cell surface represent signals growth cone is attracted to, gives surface where it can migrate - Fasciculation
-idea that if we already have a path to follow (like one made by another neuron) growth cone can follow it -EG. SPINAL CORD
4.Chemoattraction
-area where signal factor is released draws growth cone towards it -EG. NETRIN
5.Contact inhibition
-repulsion when growth cone comes into contact w something (like a specific cell type)
6.Chemorepulsion
-sigalling factor released that repulses growth cone away
