Role of dynein, dynactin, and CLIP-170 interactions in LIS1 kinetochore function.
Mutations in the human LIS1 gene cause type I lissencephaly, a severe brain developmental disease involving gross disorganization of cortical neurons. In lower eukaryotes, LIS1 participates in cytoplasmic dynein-mediated nuclear migration. We previously reported that mammalian LIS1 functions in cell division and coimmunoprecipitates with cytoplasmic dynein and dynactin. We also localized LIS1 to the cell cortex and kinetochores of mitotic cells, known sites of dynein action. We now find that the COOH-terminal WD repeat region of LIS1 is sufficient for kinetochore targeting. Overexpression of this domain or full-length LIS1 displaces CLIP-170 from this site without affecting dynein and other kinetochore markers. The NH2-terminal self-association domain of LIS1 displaces endogenous LIS1 from the kinetochore, with no effect on CLIP-170, dynein, and dynactin. Displacement of the latter proteins by dynamitin overexpression, however, removes LIS1, suggesting that LIS1 binds to the kinetochore through the motor protein complexes and may interact with them directly. We find that of 12 distinct dynein and dynactin subunits, the dynein heavy and intermediate chains, as well as dynamitin, interact with the WD repeat region of LIS1 in coexpression/coimmunoprecipitation and two-hybrid assays. Within the heavy chain, interactions are with the first AAA repeat, a site strongly implicated in motor function, and the NH2-terminal cargo-binding region. Together, our data suggest a novel role for LIS1 in mediating CLIP-170-dynein interactions and in coordinating dynein cargo-binding and motor activities.
Tai
Chin-Yin
CY
University of Massachusetts Medical School, Department of Cell Biology, Worcester, MA 01605, USA.
Dujardin
Denis L
DL
Faulkner
Nicole E
NE
Vallee
Richard B
RB
D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; D000818:Animals; D019556:COS Cells; D000072159:Dynactin Complex; D004398:Dyneins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D020409:Molecular Motor Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009363:Neoplasm Proteins; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D017434:Protein Structure, Tertiary / Q000235:genetics; D021381:Protein Transport / Q000187:drug effects / Q000235:genetics; D018911:Trinucleotide Repeats / Q000235:genetics
C000606361:DCTN2 protein, human; D000072159:Dynactin Complex; D008869:Microtubule-Associated Proteins; D020409:Molecular Motor Proteins; D009363:Neoplasm Proteins; D010446:Peptide Fragments; C076744:cytoplasmic linker protein 170; D043203:1-Alkyl-2-acetylglycerophosphocholine Esterase; C084102:PAFAH1B1 protein, human; D004398:Dyneins