Positively regulates the activity of the minus-end directed microtubule motor protein dynein. May enhance dynein- mediated microtubule sliding by targeting dynein to the microtubule plus end. Required for several dynein- and microtubule-dependent processes such as the maintenance of Golgi integrity; the peripheral transport of microtubule fragments and the coupling of the nucleus and centrosome. May be required for proliferation of neuronal precursors and neuronal migration. {ECO:0000255|HAMAP-Rule:MF_03141}.