Myosin drives retrograde F-actin flow in neuronal growth cones.
Actin filaments assembled at the leading edge of neuronal growth cones are centripetally transported via retrograde F-actin flow, a process fundamental to growth cone guidance and other forms of directed cell motility. Here we investigated the role of myosins in retrograde flow, using two distinct modes of myosin inhibition: microinjection of NEM inactivated myosin S1 fragments, or treatment with 2,3-butanedione-2-monoxime, and inhibitor of myosin ATPase. Both treatments resulted in dose-dependent attenuation of retrograde F-actin flow and growth of filopodia. Growth was cytochalasin sensitive and directly proportional to the degree of myosin inhibition, suggesting that retrograde flow results from superimposition of two independent processes: actin assembly and myosin-based filament retraction. These results provide the first direct evidence for myosin involvement in neuronal growth cone function.
Lin
C H
CH
National Yang-Ming University, Taipei, Taiwan.
Espreafico
E M
EM
Mooseker
M S
MS
Forscher
P
P
D000199:Actins / Q000378:metabolism*; D000818:Animals; D001370:Axonal Transport; D001692:Biological Transport; D002645:Chickens; D003599:Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure; D003931:Diacetyl / Q000031:analogs & derivatives / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D008845:Microinjections; D018482:Muscle, Skeletal / Q000737:chemistry; D015879:Myosin Subfragments / Q000494:pharmacology; D009218:Myosins / Q000037:antagonists & inhibitors / Q000502:physiology*; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure*
D000199:Actins; D004791:Enzyme Inhibitors; D015879:Myosin Subfragments; C004717:diacetylmonoxime; D009218:Myosins; D003931:Diacetyl; D005033:Ethylmaleimide