A motor neuron disease-associated mutation in p150Glued perturbs dynactin function and induces protein aggregation.
The microtubule motor cytoplasmic dynein and its activator dynactin drive vesicular transport and mitotic spindle organization. Dynactin is ubiquitously expressed in eukaryotes, but a G59S mutation in the p150Glued subunit of dynactin results in the specific degeneration of motor neurons. This mutation in the conserved cytoskeleton-associated protein, glycine-rich (CAP-Gly) domain lowers the affinity of p150Glued for microtubules and EB1. Cell lines from patients are morphologically normal but show delayed recovery after nocodazole treatment, consistent with a subtle disruption of dynein/dynactin function. The G59S mutation disrupts the folding of the CAP-Gly domain, resulting in aggregation of the p150Glued protein both in vitro and in vivo, which is accompanied by an increase in cell death in a motor neuron cell line. Overexpression of the chaperone Hsp70 inhibits aggregate formation and prevents cell death. These data support a model in which a point mutation in p150Glued causes both loss of dynein/dynactin function and gain of toxic function, which together lead to motor neuron cell death.
Levy
Jennifer R
JR
Department of Physiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
Sumner
Charlotte J
CJ
Caviston
Juliane P
JP
Tokito
Mariko K
MK
Ranganathan
Srikanth
S
Ligon
Lee A
LA
Wallace
Karen E
KE
LaMonte
Bernadette H
BH
Harmison
George G
GG
Puls
Imke
I
Fischbeck
Kenneth H
KH
Holzbaur
Erika L F
EL
D000818:Animals; D017209:Apoptosis / Q000235:genetics; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D020271:Heredodegenerative Disorders, Nervous System / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D008870:Microtubules / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism; D009046:Motor Neurons / Q000378:metabolism*; D017354:Point Mutation
D000072159:Dynactin Complex; D018840:HSP70 Heat-Shock Proteins; C500985:MAPRE1 protein, human; D008869:Microtubule-Associated Proteins; D004398:Dyneins