CLIPS FOR ORGANELLE-MICROTUBULE INTERACTIONS

Interactions of intracellular membranes with microtubules play a funda mental role in the dynamic organization of cytoplasmic organelles. The microtubule-based motors kinesin and cytoplasmic dynein are responsib le for directed movement of vesicles and organelles, but in vitro assa ys indicate the existence of another class of proteins linking membran es to microtubules. CLIP-170, a cytoplasmic linker protein that mediat es binding of endosomes to microtubules, provides a paradigm for under standing how these proteins may complement the role of motors in regul ating microtubule-dependent membrane trafficking.