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203 Cards in this Set

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G-Actin
monomer of microfilaments
F-Actin
helical polymer of microfilaments
None
lag phase of actin polymerization
formation of actin trimer (nucleation site)
Actin-binding proteins
versatile family of proteins that crosslink actin filaments into loose gels, bind them into stiff bundles, attach to PM, or move them
None
minimyosin (myosin 1)
motor protein of actin filaments in non-muscle cells
filamin
protein that crosslinks actin filaments into gel
spectrin
protein that crosslinks filaments to PM by their sides
fimbrin
protein that bundles actin filaments
α actinin
protein that bundles actin filaments and links actin filament to viniculin at focal contacts
gel solin
calcium dependent protein that severs or fragments actin filaments
cap-Z
protein that caps the positive end of actin
profilin
protein that binds actin monomers and inhibits polymerization
Cytochalasins
drug that blocks cell movement by binding to + end of actin to block polymerization and inhibit motility, phagocytosis, organelle and vesicle trafficking and production of lamellipodia and filopodia
Focal contacts
place that actin attaches the cell PM to extracellular matrix
Integrins
family of transmembrane proteins that link ECM's fibronectin w/ cytoplasmic actin filaments of stress fibers with attachment proteins
talin
protein that links viniculin to integrin at focal contacts
viniculin
protein that links α actinin to talin at focal contacts
integrins linkage at focal contacts
transmembrane protein that links talin to fibronectin
ankyrin
protein mainly responsible for attaching the spectrin cytoskeleton to red cell PM
filopodia
thin stiff protrusions of the cell surface that form and reform quickly and contain a bundle of actin filaments
lamellipodia
thin sheetlike processes of cell surface made of actin filament involved in cell movement
tubulin
dimer of α and β tubulin. The subunit of microtubules
protofilaments
long parallel rows into which tubulin molecules align; 13 make a microtubule
kinesins
motor protein family that move along microtubules. Associated with ER
dyneins
motor protein family that move toward the α end of microtubules. Ciliary and cytoplasmic varietys exist and are associated with the golgi
colchicine
antimitotic drug which binds to free tubulin and prevents polymerization
taxol
antimitotic drug which binds to microtubules and prevents depolymerization
γ-tubulin
ring shaped structure of centrosome which acts as the nucleation-site of a microtubule
dynamic instability
property of microtubules based on rapid polymerization and depolymerization (if GTP of plus end is hydrolyzed before the next tubulin is added)
centrioles
pair of cylindrical microtubule structures in the centrosome
arrangement of microtubules in centrioles
9 + 0
arrangement of microtubules in cilia
9 + 2
basal bodies
accumulation of centrioles beneath the PM which initiate tubulin polymerization to form the axoneme of cilia or flagella
arrangement of microtubules in basal bodies
9 + 0
axoneme
core of each cilium with 9 microtubule doublets around a pair of unjoined mt's
ciliary dynein
protein that forms the arms that extend from subfiber A and hydrolyze ATP to generate a sliding force that moves cilia
nexin
protein that forms bridges to link adjacent doublets in axonemes
radial spokes
link the doublets to the sheath in axonemes
sheath
surrounds the central microtubule pair of axonemes
effective stroke
stiff rapid forward stroke of cilia
recovery stroke
slower bending stroke of cilia
keratins
cytoplasmic IF in epithelial cells and their derivatives
vimentin
IF in cytoplasm of cells of mesenchymal origin
neurofilaments
IF in cytoplasm of neurons
lamins
IF in nucleus
filaggrin
protein in epidermis of skin that bundles keratin IF into tonofilaments
tonofilaments
bundles of keratin IF
Gated Transport
Type of protein transport from the cytosol to the nucleus
TransmembraneTransport
Type of transport from the cytosol to the ER, Mitochondria, or peroxisomes
Vesicular Transport
Type of transport from the ER to the Lysosomes, golgi and cell curface
Proteolysis
enzymatically break down proteins into constituent amino acids
Proteasomes
large complexes of proteolytic enzymes
Ubiquitin
small protein that covalently attaches to proteins to mark them for destruction and to be recognized by proteasomes
Cristae
folds of the inner mitochondrial membrane
Porins
transport proteins which form large aqueous channels through the lipid bilayer of the mitochondria's outer membrane. Form a Beta barrel
Inner Mitochondrial membrane components:
ETC enzymes (FMN, coenzyme Q, cytochrome a,b,c), succinate dehydrogenase, ATP synthase
Matrix Comparment contents:
TCA enzymes, fatty acid β-oxidation enzymes, DNA, mRNA, tRNA, rRNA, Ca and Mg granules
None
Peroxisomes
spherical to ovoid membrane bound organelles w/ 50 oxidative enzymes
catalase
uses H2O2 to oxidize other substrates like alcohols, formaldehydes and formic acid (H2O2 + R'H2 --> R' + 2 H2O)
Superoxide dismutase
naturally occuring enzyme in peroxisome that disposes of free radicals
transporter
proteinaceous ring that occupies center of Nuclear pore complex and is supported by the scaffold
Cage
on the nuclear side of the NPC fibrils converge to form this structure
Exportins
transport macromolecules (RNA) from the nucleus to cytoplasm
Importins
transport cargo (like protein subunits of ribosomes) from the cytosol to the nucleus
Contact sites
Sites of adhesion between the inner and outer mitochondrial membranes through which unfolded proteins are translocated into the matrix from the cytosol
Signal for protein to enter the mitochondria
a positive charge on the N- terminus; 20-80 amino acids in length with an α helix; removed by signal peptidase once in destination
Signal for protein to enter the nucleus; NLS
short signal located anywhere within the polypeptide which is not removed and binds to the nuclear import receptors which direct it to the NPC; unidirectional transport only
None
Signal for protein to enter peroxisomes:
3 amino acid sequence on the C-terminal that remains on protein
cistern
lumen of the endoplasmic reticulum
Signal recognition particles (SRP)
particles in the cytosol that recognize protein ER signal sequence that attach to the P site and halts translation of the protein and migrates to the rough ER with the protein
SRP receptor, docking protein
Contacts the SRP and with ribosomal receptors attaches the polysome to the cytoplasmic surface of the ER; the SRP is released and translation resumed
None
protein translocation channel
channel in ER membrane through which the growing polypeptide chain inserts into a pore in the ER membrane
None
Stop transfer sequence
sequence of hydrophobic amino acids that releases the polypeptide chain from the protein translocation channel so it will drift into the bilayer of the ER forming an α-helix of the transmembrane protein (N-terminal in the lumen)
None
start transfer sequence
er signal sequence in the middle of the polypeptide and ends up forming a transmembrane protein that passes multiple times through the PM
core region
5 sugars (3 are mannose) of the 14 oligosaccaride to glycosylate proteins
KDEL @ C-Terminal
sorting signal on proteins that directs them away from the Golgi apparatus (or to stay in the ER)
Exocytosis
process of discharging large cellular products through plasma membrane
acid phosphatase
enzyme in all lysosomes
primary lysosomes
lysosomes that haven't entered a digestive event
mannose-6-phosphate
tag for lysosomal proteins; tagged in the CGN then sorted into clathrin coated transport vesicles
None
KFERQ
signal on protein to be taken up by lysosomes
heterophagy
process whereby lysosomes digest materials taken into cells from its environment by endocytosis
Residual body
any undigested materials in the phagosome or secondary lysosome which are released back into the extracellular fluid by exocytosis
profesional phagocytes
macrophages and neutrophils
Autophagy
process by which worn out organelles are digested
autolysis
process by which lysosomal enzymes destroy their own cell
COP-I
mediated transport vesicle from CGN to ER in retrograde transport
None
COP-II
involved in anterograde transport from the ER to CGN
SNAREs
family of transmembrane proteins involved in vesicle docking with unique recognition to ensure that transport vesicles fuse with only the correct membrane
None
NSF and SNAPs
fusion proteins which catalyze membrane fusions and form fusion complex that provide the means to cross this energy barrier
apical domain
region of PM that borders luminal space
Basolateral domain
region of PM in contact with extracellular matrix
microvilli
nonmotile rigid bundle of microfilaments bound by villin with + end at the tip
terminal web
dense network of actin filaments, spectrin and cytokeratin (IF)
striated border microvilli
shortest microvilli uniform in length and found on intestinal epithelium
brush border
microvilli that are longer and less uniform and found in proximal tubules of nephrons
stereocilia
long, nonmotile microvilli found in epididymal epithelium and hair cells in the inner ear
intercellular secretory canaliculi
increase surface area between cells for exocytosis in glands and terminate blindly above basal lamina
basal infoldings
invaginations of basal PM to increase basal contact SA with ECM; form labrynth that creates basal striations with mitochondria between
What confine transport proteins to their appropriate domains by acting as a diffusion barrier?
tight junctions (zonula occludens)
zonula occludens (tight junction)
junction between cells composed of strands of long rows of specific transmembrane proteins in each cells PMs which join directly to occlude intercellular space
claudin
protein in tight junctions that form linear fibrils to create diffusion barriers for solutes, ions and water
None
occludin
transmembrane protein found in tight junctions that interacts with 4 major intracellular peripheral proteins
None
fascia occludens
junction found between capillary endothelial cells
zonula adherens
encircles each cell near apex just below tight junction. Calcium dependent
None
e-cadherin
transmembrane linker protein that mediates zonula adherens between epithelial cells
desmosomes
anchoring sites for IF to form a continuous structure throughout the tissue
basal lamina
specialized mat of ECM @ the interface between epithelium and connective tissue
α6β4
integrin found in hemidesmosomes and is the only integrin to connect intermediate filament
Junctional complex
tight junction + zonula adherens + desmosome
connexons
transmembrane proteins that align to form a hydrophilic channel between two cells in gap junctions
paracrine communication
uses local chemical mediators which are rapidly taken up and destroyed or immobilized and can only act on immediate environment
endocrine communication
specialized cells secrete hormones (steroids and water soluble hormones) that travel trough vasculature to influence cells over greater distances.
synaptic signalling
cells secrete neurotransmitters at specialized junctions (synapses)
syncytium
secondary union of originally separate cells and the precursors are nonfunctional
perinuclear cisterna
space that separates inner and outer nuclear membrane
nuclear lamina
layer made of IF (lamin) that separates the nuclear envelope from regions of peripheral heterochromatin
snRNPs- small nuclear ribonucleoprotein particles
proteins that assist in splicing to produce mRNA
Fibrillar region
nucleolar region made of ribosomal DNA that codes for the production of rRNA that is actively being transcribed
Granular region
nucleolar region made of maturing preribosomal subunit particles
Nucleolar-orgainizing regions
parts of chromosomes 13, 14, 15, 21,and 22 gene loci that encode rRNA and are located in the Nucleolus
heterochromatin
highly condensed, transcriptionally inactive chromatin
euchromatin
extended, dispersed transcriptionally active chromatin
constituitive heterochromatin
heterochromatin that is never uncoiled
facultative heterochromatin
packed chromatin that contains coding sequences and may or man not be unfolded
barr body
type of facultative heterochromatin that is never uncoiled
generation time
time of one cell cycle and dependent mainly on the G1
G1
phase of cell cycle of synthesis of proteins and specialized functions of the cell
S
phase of cell cycle when DNA is duplicated and histones are produced
G2
phase of cell cycle when the cell is prepared for mitosis
G0
phase of cells that have left the cell cycle, called end cells
stem cells
cells of same type that haven't become sufficiently specialized and can undergo mitosis and continue to cycle.
progenitor cells
cells that can proliferate but usually lose capacity for self reneal and become committed to roduce a sigle type of end cell
Cyclin-dependent kinases
proteins that for a complex with cyclins and then phosphorylate other proteins to initiate or block activities crucial to progress through cell cycle
p53
tumor suppressor protein that is a Cdk inhibitor and is absent in many cancers
D-type Cyclins
cyclins needed at the G1 checkpoint to activate Cdk 4 and 6 and allow cells to progress to the S phase
MPF- M phase promoting factor
a cyclin B-Cdc 2 complex with kinase activity that is the command to enter mitosis that accumulates in G2 at the checkpoint
kinetochore
protein structure that links centromere of chromosomes to spindle microtubules during mitosis
telomerase
enzyme that elongates existing telomere making cells 'immortal'. Only activated in cancer
satellites
DNA attached to short arms of chormosomes 13, 14, 15, 21 and 22 bye secondary constriction and contains rRNA genes. These fuse to form the nucleolus after mitosis
apoptosis
active form of cell death initiated by the cell. Programmed elimination of the cell
caspases
enzymes which degrade regulatory and structural proteins in nucleus and cytoplasm.
pyknosis
chromatin condensation that occurs in apoptosis
Starlings law of capillaries
the volume of fluid and solutes reabsorbed is approximately the volume filtered
glycosaminoglycans (GAGs)
long, inflexible, unbranched polysaccharides w/ amino sugar which are negative and have a slippery texture
aggrecan
proteoglycan expressed in cartilage with keratan sulfate and chondroitin sulfate as the GAGs
perlecan
proteoglycan found with all cells making basal lamina that is made with heparan sulfate
RGD sequence
simple 3-peptide sequence that is the integrin binding sites of many adhesive proteins
fibronectin
large plycoprotein dimer with binding sites for extracellular components and integrins. The main product of fibroblasts. Involved in adhesion of cells to ECM
laminin
large glycoprotein composed of 3 large polypeptide chains with binding sites for heparan sulfate, type IV collagen, entactin and PM. Located in the Basal Lamina
Entactin
glycoprotein that binds to laminin and type IV collagen in the basal lamina
Type I Collagen
most common collagen; secreted by fibroblasts and provides tensile strenth in connective tissues
Type II Collagen
fill the extracellular matrix of cartilage
Type III Collagen
called reticular fibers; highly glycosylated collagen that forms thin fibers
Type IV Collagen
Sheets that surround organs and epithelia. Found in the basal lamina and external lamina for support and filtration
Type VII collagen
anchoring collagen found in epidermal-dermal junctions that links type IV collagen of the basal lamina to underlying connective tissue
procollagen peptidase
protein on E-surface of PM that cleaves registration peptides from procollagen to form tropocollagen
propeptides or registration peptides
guide the formation of triple helical structure and prevent intracellular formation of collagen fibers
lysyl oxidase
forms covalent crosslinks between tropocollagen molecules and tropoelastin molecules
fibrillin
glycoprotein distributed mainly as microfibrils on the elastic fiber surface
basal laminae
mats of specialized ECM (mostly type IV collagen) that underlie all epithelial cell cheets and tubes and surround individual muscle, fat and schwann cells
lamina rara
layer of basal lamina adjacent to basal PM and made of heparan sulfate (perlecan)
lamina densa
electron dense layer of basal lamina just beneath the lamina rara. Made mostly of type IV collagen
lamina reticularis
3rd layer of basal lamina that isn't always present. Connects the basal lamina to connective tissue below and composed of type III collagen
Function of Na+ channels
generating and propagating action potentials in excitable cells
function of K+ channels
control of excitability and shaping of electrical signals
Function of Ca++ channels
neurotransmitter release, muscle contraction and intracellular signalling pathways
hyperkalemic periodic paralysis
an Na+ chanenelopathy revealed when extracellular K+ is raised. Channel doesn't inactivate properly and action potential can't develop.
tetrodotoxin (TTX)
neurotoxin that is highly specific blocker of voltage-gated Na+ channels. Leads to respiratory paralysis and is found in puffer fish
local anesthetics- novacain, lidocain
block voltage gated Na channels in axon and prevent conduction of nerve impulses
Lamber-eaton Myasthenic Syndrome (LEMS_
autoimmune disease that impairs calcium influx and reduces transmitter relase at neuromuscular junction resulting in muscle weakness
halothan
anestheic that opens the leak K+ channels
nifedipin and verapamil
drugs used in the treatment of cardiovascular disease by blocking Ca++ channels
3,4 Diaminopyridine
drug used to treat LEMS by blocking K+ channel and prolongs the action potential
acetylcholine receptors
ligand gated channels at neuromuscular junction involved in excitatory neurotransmission
glutamate receptors
ligand gated channels at CA3-CA1 hippocampal synapse
GABA receptors
ligand gated channels at hippocampal synapses
Nicotinic acetylcholine receptor
ligand gated channel at neuromuscular junction that bind Ach and allows Na+ and K+ flux and induces depolarization which increases Ca++ and results in muscle contraction
hyperpolarized
a membrane potential which becomes more negative
depolarized
a membrane potential which becomes less negative
acetylcholinesterase
breaks Ach into acetate and choline and terminates signal
congenital myasthenic syndrome
this is a slow channel syndrome present at birth that is caused by mutations on Ach receptors causing weakness, rapid fatigue, and muscle atrophy
D-Tubocurarine
competetive inhibitor of Ach that causes paralysis and death by asphyxiation
Vercoronium, Pancuronium, and Rocuronium
synthetic chemicals that cause parlaysis by competitively inhibiting Ach receptors. Used in surgical procedures
α bungarotoxin
snake toxin that binds competetively and irriversibly to Ach receptors
Succinycholine
Ach R agonist that binds and causes depolarization and is used as a muscle relaxant
Nicotine
Ach R agonist that binds at same sites as ACh and can cause muscle contraction
Myasthenia Gravis
autoimmune neuromuscular disease caused by the destruction of peripheral NACh receptors causing muscle weakness, movement deficit and fatigue
None
Picrotoxin
noncompetetive blocker of GABA
Benzodiazapine
anxiolytic drug that increases GABA activity and is used for anxiety disorders and insomnia
Barbituates
anticonvulsant and sedative drug that increases GABA activity. Used for epilepsy, anesthesia and anxiety
Hormone response elements
DNA sequences where steroid receptor complexes bind and regulate rate of transcription
Gs
G-protein that stimulates AC and activates protein kinase A
Gi
G-protein that inhibits AC and inhibits protein kinase A
Gq
G-protein that is coupled to Phospholipase C which increases DAG, and in turn IP3 and Ca++ and activates protein kinase C
Cholera toxin
bacterial toxin that stimulates Gs and causes and excess production of cAMP
Pertussis Toxin
bacterial toxin that inhibits Gi and cases excess cAMP
Sos
guanine nucleotide exchange factor for Ras that is attracted by Grb2 in the signaling event of tyrosine kinase receptor
GTPase activating proteint (GAP)
hydrolyzes GTP and inactivates Ras
Restriction Point
the point in G1 when the cell cycle stops being GF dependent
Oncogene
a mutated protein of the cell cycle control system that is constituitively activated, Ras, myc, fos, jun
Tumor supressor gene
protein that inhibits cell cycle progression- Rb, p53
Akt pathway
signaling effect of neurotrophins binding to receptor tyrosine kinase that prevents cell death