title: Attachment of transported vesicles to microtubules in axoplasm is facilitated by AMP-PNP.
abstract: Axoplasm extruded from the squid giant axon has been used to analyse the molecular mechanisms of intracellular vesicle transport. Using video-enhanced light microscopy, vesicle transport can be observed directly on individual microtubules at the edge of the axoplasm. Here we report that AMP-PNP (adenyl-5'-yl imidodiphosphate), a non-hydrolysable analogue of ATP, reversibly inhibited vesicle transport. Moreover, vesicles in solution attach to the microtubules and form relatively stable complexes. AMP-PNP may produce this effect by binding to an ATP-binding site on the transport machinery, thereby stabilizing the motility complex that is normally formed by a transported vesicle, an ATPase and a microtubule. The effects of AMP-PNP on the vesicle transport system indicate that the enzymatic machinery of this system differs significantly from that of the actomyosin system or the dynein-microtubule system.
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives* / Q000494:pharmacology; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology*; D000818:Animals; D001369:Axons / Q000187:drug effects* / Q000502:physiology; D002465:Cell Movement / Q000187:drug effects; D049832:Decapodiformes; D066298:In Vitro Techniques; D008870:Microtubules / Q000187:drug effects* / Q000502:physiology
chemical_list: D000266:Adenylyl Imidodiphosphate; D000255:Adenosine Triphosphate