Microtubules with altered assembly kinetics have a decreased rate of kinesin-based transport.
Microtubules treated with the gamma-diketone 2,5-hexanedione (2,5-HD) have altered assembly behavior characterized by precocious nucleation and rapid elongation. By measuring the rate of microtubule transport, we have examined the potential functional significance of this 2,5-HD-induced microtubule modification. 2,5-HD-treated microtubules were transported at only 70% of the rate of control microtubules in a simple kinesin-based motility assay on glass coverslips using video and computer enhanced differential interference contrast microscopy. Since 2,5-HD is capable of forming both pyrrole adducts and crosslinks with tubulin, the contributions of pyrrole formation and crosslinking to slowed microtubule transport were determined. 3-Acetyl-2,5-hexanedione (AcHD), a pyrrole forming, non-crosslinking congener of 2,5-HD which does not alter microtubule assembly, did not produce slowed microtubule transport as occurs with 2,5-HD. However, glutaraldehyde, a pyrrole-independent crosslinking agent which alters microtubule assembly in the same way as 2,5-HD, slowed microtubule transport. These results indicate that a 2,5-HD-induced microtubule modification, possibly a crosslink-related conformational change, produces both an alteration in the kinetics of assembly and an alteration in the microtubule-motor interaction.
Redenbach
D M
DM
Department of Pathology, Brown University, Providence, Rhode Island 02912.
Richburg
J H
JH
Boekelheide
K
K
D000818:Animals; D001693:Biological Transport, Active; D002417:Cattle; D003432:Cross-Linking Reagents / Q000494:pharmacology* / Q000633:toxicity; D005976:Glutaral / Q000494:pharmacology; D006588:Hexanones / Q000494:pharmacology* / Q000633:toxicity; D016547:Kinesins / Q000378:metabolism*; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*
D003432:Cross-Linking Reagents; D006588:Hexanones; C087396:3-acetyl-2,5-hexanedione; C011269:2,5-hexanedione; D016547:Kinesins; D005976:Glutaral