Lecture 15 - Dynein

Intracellular motility

dyneins

used in flagella + cilia

use ATP hydrolysis to move towards - ends of MT

dynein-1

eukaryotic cytoplasmic dynein

dynein-2

prokaryotic cytoplasmic dynein

dynein discovery

Gibbons

Richard Vallee

Gibbons 1963

removed membrane from axoneme

saw 9+2 arragement

no arms = ATPase activity

Vallee 1987

dynein needed for retrograde transport

moves towards - end in cell center

MAPC = cytoplasmic dynein

cytoplasmic dynein

AAA ATPase

moves to - end of MT

dynein structure

6 ATPase domains in large heavy chains

=2 globular heads

n-terminus + light chains + intermediate chains + cargo

ATPase domains

AAA1 = main ATP hydrolysis domain

AAA2 5 6 = no ATP hydrolysis

AAA3 4 = ATP hydrolysis

dynein stalks

come out of AAA4

MT binding domain

helical domain

binds to cleft a and B tubulin

dynein light chains

Tctex-1

LC7/roadblock

LC8

Tctex-1

promotes self association of intermediate chains

LC7/roadblock

separates intermediate chains,

dimerizes dynein

LC8

dimerizes dynein

binding hub for other proteins

dynein movement

stalk bends and rotates head

MT binding site pointed @ - end

swings 8-24nm

not processive

dynactin

dynein activator

11 protein complex

23 subunits

step in any direction (8-32nm)

ARP 1 - spectrin + dynein - dynactin =

binding to phospholipids

movement towards + end

kinesins over power dyneins

CLIP170 and EB1 recruit p150 to + end

dynactin binds to it

movement problems

roadblocks and microtubule intersections

can’t pause movement bc cargo will accumulate

movement block solution

endosomes fission = smaller

vesicles will switch MT tracks

dynein heavy chain -/-

embryologically lethal

altered dynein

peripheral neuropathy

spinal muscle atrophy

malformation of cortical development

axonal transport defects

alzheimers

parkinsons

huntingtons