GSBS Student Publications

Title

Colocalization of cytoplasmic dynein with dynactin and CLIP-170 at microtubule distal ends

UMMS Affiliation

Graduate School of Biomedical Sciences; University of Massachusetts Medical School

Date

4-23-1999

Document Type

Article

Medical Subject Headings

Animals; COS Cells; Cell Cycle; Detergents; Dynein ATPase; Golgi Apparatus; Microtubule-Associated Proteins; effects; Microtubules; Neoplasm Proteins; Nocodazole; Octoxynol; Temperature

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

Cytoplasmic dynein is a minus end-directed microtubule motor responsible for centripetal organelle movement and several aspects of chromosome segregation. Our search for cytoplasmic dynein-interacting proteins has implicated the dynactin complex as the cytoplasmic dynein 'receptor' on organelles and kinetochores. Immunofluorescence microscopy using a total of six antibodies generated against the p150Glued, Arp1 and dynamitin subunits of dynactin revealed a novel fraction of dynactin-positive structures aligned in linear arrays along the distal segments of interphase microtubules. Dynactin staining revealed that these structures colocalized extensively with CLIP-170. Cytoplasmic dynein staining was undetectable, but extensive colocalization with dynactin became evident upon transfer to a lower temperature. Overexpression of the dynamitin subunit of dynactin removed Arp1 from microtubules but did not affect microtubule-associated p150Glued or CLIP-170 staining. Brief acetate treatment, which has been shown to affect lysosomal and endosomal traffic, also dispersed the Golgi apparatus and eliminated the microtubule-associated staining pattern. The effect on dynactin was rapidly reversible and, following acetate washout, punctate dynactin was detected at microtubule ends within 3 minutes. Together, these findings identify a region along the distal segments of microtubules where dynactin and CLIP-170 colocalize. Because CLIP-170 has been reported to mark growing microtubule ends, our results indicate a similar relationship for dynactin. The functional interaction between dynactin and cytoplasmic dynein further suggests that this these regions represent accumulations of cytoplasmic dynein cargo-loading sites involved in the early stages of minus end-directed organelle transport.

Rights and Permissions

Citation: J Cell Sci. 1999 May;112 ( Pt 10):1437-47.

Related Resources

Link to Article in PubMed

Journal Title

Journal of cell science

PubMed ID

10212138