KINESIN-MEDIATED ORGANELLE TRANSLOCATION REVEALED BY SPECIFIC CELLULAR MANIPULATIONS

The distribution of membrane-bound organelles was studied in cultured hippocampal neurons after antisense oligonucleotide suppression of the kinesin-heavy chain (KHC). We observed reduced 3,3'-dihexyloxacarbocy anine iodide (DiOC6(3)) fluorescent staining in neurites and growth co nes. In astrocytes, KHC suppression results in the disappearance of th e DiOC6(3)-positive reticular network from the cell periphery, and a p arallel accumulation of label within the cell center. On the other han d, mitochondria microtubules and microfilaments display a distribution that closely resembles that observed in control cells. KHC suppressio n of neurons and astrocytes completely inhibited the Brefeldin A-induc ed spreading and tabulation of the Golgi-associated structure enriched in mannose-6-phosphate receptors. In addition, KHC suppression preven ts the low pH-induced anterograde redistribution of late endocytic str uctures. Taken collectively, these observations suggest that in living neurons, kinesin mediates the anterograde transport of tubulovesicula r structures originated in the central vacuolar system (e.g., the endo plasmic reticulum) and that the regulation of kinesin-membrane interac tions may be of key importance for determining the intracellular distr ibution of selected organelles.