Cytoskeleton

Question 0

What mutation cause liscencephaly?

Answer 0

R403H on αβ Tubulin interface prevents MAP binding

Question 1

What autosomal characteristic is hereditary spastic paraplegia?

Answer 1

Dominant

Question 2

What mutation cause hereditary spastic paraplegia?

Answer 2

Misense mutation in Kif5a motor domain for transport of mitochondria in neurones

Question 3

Nemaline myopathy effects which muscle type?

Answer 3

Nebulin in skeletal muscle

Question 4

Myosin 7a mutations cause blindness and deafness. What is the syndrome?

Answer 4

Usher

Question 5

Dystrophin links what components of the muscle?

Answer 5

Gamma actin at Z discs is linked to αβ-dystroglycan membrane (ECM) protein at costameres

Question 6

Griscelli syndrome has mutated …?

Answer 6

Myosin 5a (Rab27a)

Question 7

Emery dreiffuss muscular dystrophy, limb girdle muscular dystrophy, dilated cardiomyopathy, Charcot Marie tooth disease have mutated ….?

Answer 7

Lamin A

Question 8

Progeria is caused by lamin A mutation ?

Answer 8

E145K in lamin A

Question 9

The lamin A mutations in progeria cause ?

Answer 9

No filament polymerisation so weak to mechanical damage causing rupture and senescence

Question 10

What is desmin?

Answer 10

A muscular intermediate filament

Question 11

Epidermolysis bullosa is caused by ?

Answer 11

Keratin mutations detaching cells from ECM causing blistering

Question 12

What is the structure of microtubules?

Answer 12

αβ tubulin dimers

25nm diameter

Question 13

What are the 3 types of cytoskeleton filament?

Answer 13

actin
intermediate
microtubules

Question 14

Where do microtubules grow from?

Answer 14

-/slow growing end in Microtubule Organising Centre near centrosome

Question 15

What are microtubules used for?

Answer 15

track for kinesin/dynein motors to move organelles
spindles in mitosis
cillia and flagella
projections for intercellular interactions

Question 16

What is the function of tau?

Answer 16

Binds microtubules to stabilise by reducing dynamics

Question 17

How are tauopathies caused?

Answer 17

Hyperphosphorylation detaches Tau
Tau forms paired helical filaments
Microtubules stabilise/depolymerise to form neurofibrillary tangles

Question 18

How many genes encode kinesins?

Answer 18

40 in humans

Question 19

What is the structure of actin?

Answer 19

monomers polymerised into left helix

4-7nm diameter

Question 20

What are the different types of actin?

Answer 20

α in muscle sarcomeres

β and γ in non-muscle

Question 21

Is a myopathy progressive?

Answer 21

No

Question 22

What are the actin related diseases?

Answer 22

Duchenne muscular dystrophy
Usher syndrome
Griscelli syndrome
Neamiline cogenital myopathy

Question 23

What are the intermediate filament diseases?

Answer 23

Epidermis bullosa
Progeria
Emery-Drieffus muscular dystrophy

Question 24

What are the microtubule diseases?

Answer 24

Tauopathies/ alzhiemers etc
Kinesin/ hereditary spastic paraplegia
tubulin/ Liscencephaly

Question 25

What are the different types of intermediate fibres?

Answer 25

keratin in epithelium
Vimentin in neurones and fibroblasts
Desmin in muscle

Question 26

What is the structure of intermediate filaments?

Answer 26

10nm,
not dynamic
no associated proteins

Question 27

What is the function of intermediate filaments?

Answer 27

cell-cell and cell-ECM interactions