Real-time visualization of processive myosin 5a-mediated vesicle movement in living astrocytes
Graduate School of Biomedical Sciences; Department of Cellular and Molecular Physiology; Department of Physiology; Program in Molecular Medicine
Medical Subject Headings
Actins; Animals; Animals, Newborn; Astrocytes; Base Sequence; Cell Movement; DNA Primers; Myosins; Rats
Life Sciences | Medicine and Health Sciences
Recycling endosomes in astrocytes show hormone-regulated, actin fiber-dependent delivery to the endosomal sorting pool. Recycling vesicle trafficking was followed in real time using a fusion protein composed of green fluorescent protein coupled to the 29-kDa subunit of the short-lived, membrane-bound enzyme type 2 deiodinase. Primary endosomes budded from the plasma membrane and oscillated near the cell periphery for 1-4 min. The addition of thyroid hormone triggered the processive, centripetal movement of the recycling vesicle in linear bursts at velocities of up to 200 nm/s. Vesicle migration was hormone-specific and blocked by inhibitors of actin polymerization and myosin ATPase. Domain mapping confirmed that the hormone-dependent vesicle-binding domain was located at the C terminus of the motor. In addition, the interruption of normal dimerization of native myosin 5a monomers inactivated vesicle transport, indicating that single-headed myosin 5a motors do not transport cargo in situ. This is the first demonstration of processive hormone-dependent myosin 5a movement in living cells.
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Citation: J Biol Chem. 2001 Sep 21;276(38):35652-9. Epub 2001 Aug 9. Link to article on publisher's site