Kinesin and Dynein motors

Kinesin and Dynein motors are responsible for numerous microtubule-dependent transport events in eukaryotic cells. The organisation of the ER and Golgi depends on the orientation of microtubules and motor activity. If colcemid is added to cells all ER and Golgi structure is disrupted. Vesicle transport is also blocked. As the microtubules re-grow the ER does so along extending microtubules, starting at the MTOC. Kinesins direct exocytosis (towards the plasmamembrane) and dynein directs endocytosis (away from the plasmamembrane).