A glue for microtubule cargos

Vaughan et al., reporting on page 305, have used live-cell imaging to characterize the dynamic interactions of dynactin with growing microtubule plus-ends. The results provide substantial new insights into the regulation of these interactions, and suggest a new model for organelle transport and anchoring.

Previous work identified the p150^Glued subunit of dynactin as a specific binding partner for cytoplasmic dynein. To characterize this protein further, the authors tracked GFP-tagged p150^Glued using time-lapse imaging. P150^Glued associated with growing microtubule plus-ends to form “comet tails,” which reflect binding followed by delayed release. The delay suggests that p150^Glued binding to the growing plus-ends may be followed by multiple molecular events at the microtubule tip, including the phosphorylation of p150^Glued that mediates its release.

Contact of p150^Glued comet tails with Golgi-derived membranes...