Abstract
CLIP-170 is a plus-end tracking protein which may act as an anticatastrophe factor. It has been proposed to mediate the association of dynein/dynactin to microtubule (MT) plus ends, and it also binds to kinetochores in a dynein/dynactin-dependent fashion, both via its C-terminal domain. This domain contains two zinc finger motifs (proximal and distal), which are hypothesized to mediate protein-protein interactions. LIS1, a protein implicated in brain development, acts in several processes mediated by the dynein/dynactin pathway by interacting with dynein and other proteins. Here we demonstrate colocalization and direct interaction between CLIP-170 and LIS1. In mammalian cells, LIS1 recruitment to kinetochores is dynein/dynactin dependent, and recruitment there of CLIP-170 is dependent on its site of binding to LIS1, located in the distal zinc finger motif. Overexpression of CLIP-170 results in a zinc finger-dependent localization of a phospho-LIS1 isoform and dynactin to MT bundles, raising the possibility that CLIP-170 and LIS1 regulate dynein/dynactin binding to MTs. This work suggests that LIS1 is a regulated adapter between CLIP-170 and cytoplasmic dynein at sites involved in cargo-MT loading, and/or in the control of MT dynamics.
The first two authors contributed equally to this work.
We thank Anne Moreau for technical assistance. Jean-Baptiste Sibarita is acknowledged for his expertise with image deconvolution.
This work was supported in part by the Fritz Thyssen Stiftung Foundation, HFSP grant no. RG283199 9, March of Dimes grant no. 6-FY01-5, and the Minerva Foundation (to O.R.) and by the Association pour la Recherche contre le Cancer (Villejuif, France) (to J.R.D.M.). O.R. is an Incumbent of the Aser Rothstein Career Development Chair in Genetic Diseases.