About this Biochemistry, Genetics and Molecular Biology article

Dynamic localization of myosin‐I to endocytic structures in Acanthamoeba by E. Michael Ostap; Pamela Maupin; Steven K. Doberstein; Ivan C. Baines; Edward D. Korn; Thomas D. Pollard is a Biochemistry, Genetics and Molecular Biology article available to read on EtoBox.

## Abstract We used fluorescence microscopy of live __Acanthamoeba__ to follow the time course of the concentration of myosin‐I next to the plasma membrane at sites of macropinocytosis and phagocytosis. We marked myosin‐I with a fluorescently labeled monoclonal antibody (Cy3‐M1.7) introduced into the cytoplasm by syringe loading. M1.7 binds myosin‐IA and ‐IC without affecting their activities, but does not bind myosin‐IB. Cy3‐M1.7 concentrates at two different macropinocytic structures: large circular membrane ruffles that fuse to create macropinosomes, and smaller endocytic structures that occur at the end of stalk‐like pseudopodia. These dynamic structures enclose macropinosomes every 30–60 s. Cy3‐M1.7 accumulates rapidly as these endocytic structures form and dissipate rapidly after they internalize. Double labeling fixed cells with Cy3‐M1.7 and polyclonal antibodies specific for myosin‐IA, ‐IB, or ‐IC revealed that all three myosin‐I isoforms associate with macropinocytic structures, but individual structures vary in their myosin‐I isoform composition. Myosin‐I and actin also concentrate transiently at sites where amoebae ingest yeast or the pseudopodia of neighboring cells (he

Author

E. Michael Ostap; Pamela Maupin; Steven K. Doberstein; Ivan C. Baines; Edward D. Korn; Thomas D. Pollard

Publisher

John Wiley and Sons; Wiley (John Wiley & Sons); John Wiley & Sons Inc.; Wiley (ISSN 0886-1544)

Published

2002

Language

EN

Field

Biochemistry, Genetics and Molecular Biology (Life Sciences)