Different axoplasmic proteins generate movement in opposite directions along microtubules in vitro.
Single microtubules from squid axoplasm support bidirectional movement of organelles. We previously purified a microtubule translocator (kinesin) that moves latex beads in only one direction along microtubules. In this study, a polar array of microtubules assembled off of centrosomes in vitro was used to demonstrate that kinesin moves latex beads from the minus to the plus ends of microtubules, a direction that corresponds to anterograde transport in the axon. A crude solubilized fraction from squid axoplasm (S1a), however, generates bidirectional movement of beads along microtubules. Retrograde bead movement (1.4 micron/sec) is inhibited by N-ethylmaleimide and 20 microM vanadate while anterograde movement (0.6 micron/sec) is unaffected by these agents. Furthermore, a monoclonal antibody against kinesin, when coupled to Sepharose, removes the anterograde, but not the retrograde, bead translocator from S1a. These results indicate that there is a retrograde bead translocator which is pharmacologically and immunologically distinct from kinesin.
Vale
R D
RD
Schnapp
B J
BJ
Mitchison
T
T
Steuer
E
E
Reese
T S
TS
Sheetz
M P
MP
D000818:Animals; D000911:Antibodies, Monoclonal; D001370:Axonal Transport / Q000187:drug effects; D001369:Axons / Q000032:analysis* / Q000648:ultrastructure; D049832:Decapodiformes; D005033:Ethylmaleimide / Q000494:pharmacology; D016547:Kinesins; D007840:Latex; D008863:Microspheres; D008868:Microtubule Proteins / Q000302:isolation & purification*; D008870:Microtubules / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000302:isolation & purification* / Q000502:physiology*; D014638:Vanadates; D014639:Vanadium / Q000494:pharmacology
D000911:Antibodies, Monoclonal; D007840:Latex; D008868:Microtubule Proteins; D009419:Nerve Tissue Proteins; D014639:Vanadium; D014638:Vanadates; D016547:Kinesins; D005033:Ethylmaleimide