Biochemistry & Molecular Pharmacology
Graduate School of Biomedical Sciences; Department of Cell Biology
Life Sciences | Medicine and Health Sciences
We observe that one of the high molecular mass microtubule-associated proteins (MAPs) from brain exhibits nucleotide-dependent binding to microtubules. We identify the protein as MAP IC, which was previously described in this laboratory as a minor component of standard microtubule preparations (Bloom, G.S., T. Schoenfeld, and R.B. Vallee, 1984, J. Cell Biol., 98:320-330). We find that MAP 1C is enriched in microtubules prepared in the absence of nucleotide. Kinesin is also found in these preparations, but can be specifically extracted with GTP. A fraction highly enriched in MAP 1C can be prepared by subsequent extraction of the microtubules with ATP. Two activities cofractionate with MAP 1C upon further purification, a microtubule-activated ATPase activity and a microtubule-translocating activity. These activities indicate a role for the protein in cytoplasmic motility. MAP 1C coelectrophoreses with the beta heavy chain of Chlamydomonas flagellar dynein, and has a sedimentation coefficient of 20S. Exposure to ultraviolet light in the presence of vanadate and ATP results in the production of two large fragments of MAP 1C. These characteristics suggest that MAP 1C may be a cytoplasmic analogue of axonemal dynein.
DOI of Published Version
J Cell Biol. 1987 Sep;105(3):1273-82.
The Journal of cell biology
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Paschal BM, Shpetner HS, Vallee RB. (1987). MAP 1C is a microtubule-activated ATPase which translocates microtubules in vitro and has dynein-like properties. GSBS Student Publications. https://doi.org/10.1083/jcb.105.3.1273. Retrieved from https://escholarship.umassmed.edu/gsbs_sp/967