Ctb Exam 1 Lectures 1-3

Front 1

What are the approximate resolving powers of the eye, LM, and EM?

Back 1

Eye = 0.2 mm
LM = 0.2 um
EM = 0.2 nm

(1um = 1000 nm)

Front 2

Intrinsic scales in LM & EM images

Back 2

RBC - 7 um in diameter
Ribosomes - 25 nm in diameter
Mitochondria - 0.5 um in thickness
microtubule - 22 nm in thickness
plasma membrane - 10 nm in thickness

Front 3

Structure and families of actin

Back 3

double strand of globular proteins (G actin) that wrap around each other like pearls

alpha - skeletal muscle
beta, gamma - muscle and nonmuscle cells

Front 4

Spectrin

Back 4

anchors / cross-links MFs

Front 5

Tropomyosin

Back 5

binds to groove & stabilizes MF

Front 6

alpha actinin

Back 6

bundle MFs

Front 7

fimbrin

Back 7

bundle MFs

Front 8

flamin

Back 8

links MFs into gels

Front 9

gelsolin

Back 9

severs MFs

Front 10

thymosin

Back 10

bind g-actin monomers

Front 11

profilin

Back 11

bind g-actin monomers

Front 12

functions of actin

Back 12

membrane cytoskeleton, vesicle movement, cytokinesis, cell locomotion, cell shape, cell adhesion, muscle contractility, metabolic compartmentation

Front 13

drugs affecting actin

Back 13

phallotoxin - binds and stabilizes fragments so they can't be broken down
latrunculin - binds subunits, preventing polymerization
cytochalasin - caps the barbed end, preventing polymerization
swinholide - severs fragments

Front 14

actin and human pathologies

Back 14

Wiskott-Aldrich syndrome - mutation in WAS protein which is critical for rapid assembly of MFs
ALS - mutated profilin 1 gene
cardiomyopathy (familial hypertrophic or idiopathic dilated) - altered actin organization affects contraction (FH) or force transmission from sarcomere (ID)
cancer - can convert stable cells to mobile cells
celiac - actin in microvilli = autoantigen

Front 15

structure of microtubules

Back 15

heterodimers of alpha and beta tubulins aligned end to end in protofilaments, 13 joined together to form a hollow tube

Front 16

structure of basal bodies and centrioles

Back 16

9 sets of circumferentially arranged triplet microtubules

Front 17

how are microtubules nucleated?

Back 17

rings of gamma tubulin in the MTOC

Front 18

structure of cilia and flagella

Back 18

9 sets of microtubule doublets around a single pair

Front 19

stathmin

Back 19

binds to microtubules, preventing their phosphorylation, thus promoting disassembly

Front 20

katanin

Back 20

severs microtubules

Front 21

spastin

Back 21

severs microtubules

Front 22

tau

Back 22

MAP found in neurons - stabilizes MTs and promotes their assemnly

Front 23

functions of microtubules

Back 23

interphase - transport of organelles, cell polarity and shape, consolidation of cell movements

mitosis / meiosis - spindle formation, segregation of chromosomes

Front 24

Drugs and Microtubules

Back 24

Taxol - stabilizes MTs

Vincristine - destabilizes MTs

both block cell division of malignant cells, used in chemo

Front 25

Alzheimer's

Back 25

tau aggregates and forms tangles whose distribution correlates with loss of synaptic connection and dimentia

Front 26

frontotemporal dementia and parkinsonism

Back 26

mutated tau leads to degeneration of neurons

Front 27

hereditary spastic paraplegia w/ MTs

Back 27

usually due to mutated spastin

leads to stiffness and spasticity of lower limbs

Front 28

lissencephaly (3 genes could be affected)

Back 28

Lis 1 - neurons fail to migrate, layering of cortex fails to form
doublecortin - males have smooth cortex, females get double cortex
tubulin alpha 1a - classic lissencephaly, smooth cortex with no folds

Front 29

congenital fibrosis of the extraocular muscles type 3

Back 29

mutated beta 3 tubulin causes defect in axon path finding

Front 30

Structure and families of intermediate filaments

Back 30

rope-like subunits with a coiled core

Types I and II - keratins in epithelial cells
Type III - Vimentin (fibroblast), glial fibrillary actin protein (astrocytes) desmin (smooth muscle)
Type IV - neurofilaments
Type V - lamins in nuclear envelope

Front 31

BPAG

Back 31

1e - binds keratin to hemidesmosomes - mutants blister

1n - cross link neurofilaments to cytoskeleton - mutants have axonopathy

Front 32

filaggrin

Back 32

aggregates keratin

Front 33

emerin

Back 33

integral inner nuclear membrane that interacts with lamins

Front 34

plectin

Back 34

links keratin to cytoskeleton - mutants blister

Front 35

features and functions of intermediate filaments

Back 35

most cell specific, flexible even when bundled, most stable, give mechanical strength, structural not motile functions, skin and hair structure, act via desmosomes, nonpolar filaments (assembly / disassembly occurs in the middle)

Front 36

Epidermolysis Bullosa Simplex

Back 36

blistering occurs wherever keratin is mutated

variant form occurs with muscular or sensory neuron involvement when plectin or BPAG 1 (keratin associated proteins) are mutated

Front 37

ALS or Charcot Marie Tooth Disesase and IFs

Back 37

neurofilaments accumulate in the initial segment of the axon

Front 38

Progeria, cardiomyopathy and muscular dystrophy and lamin

Back 38

mutations in lamin lead to inability to form a stable nuclear envelope

Front 39

MT vs. MF vs. IF polymerization

Back 39

MT - GTP needed on beta tubulin

MF - ATP is hydrolyzed after a g-actin molecule is added

IF - lack polarity so do not require ATP or GTP

Front 40

AMP-PNP

Back 40

a competitive inhibitor of myosin and dynein but stabilizes binding of organelles to microtubules to kinesins

Front 41

classes of myosins

Back 41

I - monomeric, plays role in endocytosis and hearing / balance (via calcium channels)
II - most common - all muscle myosins are type II but they're also found in nonmuscle cells - locomotion and cytokinesis
V - delivery of vesicles to plasma membrane

Front 42

functions of myosins

Back 42

cell motility - via filopodia and lamellopodia
cytokinesis - assemble and contract actin ring that constricts cytoplasm
structural support - microville, stereocilia
cytoskeleton - move organelles for exocytosis

BINDS TO ACTIN

Front 43

Griscelli syndrome

Back 43

defects in myosin V so pigment granule vesicles aren't delivered to hair particles ==> partial albinism

Front 44

Usher syndrome

Back 44

sensorineural hearing loss & retinitis pigmentoia due to mutated myosin VII

Front 45

hypertrophic cardiomyopathy

Back 45

leading cause of sudden cardiac death in young adults - all mutations cause a defect in the ability of the muscle to contract

defects can occur in the following genes: MYH7, MYL3, MYL2, MYH7

Front 46

MAP 1C

Back 46

cytoplasmic form of dynein - moves things from the periphery to the center of the cell

Front 47

dynactin

Back 47

links cytoplasmic dynein to centrosomal material, actin cytoskeleton, and membranes

Front 48

dynamitin

Back 48

involved in dynactin - dynein interactions but when overexpressed, the golgi fragments and disperses

Front 49

spinal muscular atrophy

Back 49

mutations in the heavy chain gene of dynein lead to peripheral sensory issues

Front 50

ALS w/ dynein

Back 50

mutations in dynein - dynactin complex

Front 51

Lissencephaly w/ dynein

Back 51

mutated Lis1, thought to anchor dyneins during embryonic development

Front 52

situs inversus

Back 52

reversal or randomization of normal organ locations - mutations in flagellar dyneins during cytokinesis that prevents appropriate gradient from forming

Front 53

syndromic male sterility

Back 53

defects in dynein affect flagellum of sperm

Front 54

kinesins

Back 54

bind to ATP and MTs - movement toward plus end of MT - associated with vesicles, mitochondria, lysosomes

Front 55

hereditary spastic paraplegia w/ kinesin

Back 55

mutation creates a nonfunctional motor - essential to development of embryos so lethal if homozygous - adult onset for heterozygotes

Front 56

kinesins and human pathology

Back 56

congenital fibrosis of the extraocular muscles, Alzheimer's, Parkinson's, Huntington's, ALS - changes in axonal trafficking due to defective motor - loss of connectivity

Front 57

mitosis and motors

Back 57

interphase - motors present for trafficking, transport of cytoskeleton & motility
prophase - dynein orients spindles, positions daughter cells
metaphase - kinesin related proteins are required
anaphase - dyneins pull chromatids to opposite ends
cytokinesis - myosin II contracts to pinch cells apart