TY - JOUR
T1 - Dynamics of yeast myosin I
T2 - Evidence for a possible role in scission of endocytic vesicles
AU - Jonsdottir, Gudrun A.
AU - Li, Rong
N1 - Funding Information:
We are grateful to the Yeast Resource Center at University of Washington for the DsRed plasmid, Coumaran Egile for the use of the Arc40-YFP strain, Thomas Lipkin for help with plasmid construction, Jennifer Waters Shuler at the Nikon-Harvard Imaging Center for help on fluorescence microscopy, and Maria Ericsson for help on electron microscopy. We thank Lynn VerPlank, Roland Wedlich-Soldner, Shawnna Buttery for critical reading of the manuscript, and all members of the Li laboratory for helpful discussion. This work was supported by the National Institutes of Health grant GM057063 to R.L.
PY - 2004/9/7
Y1 - 2004/9/7
N2 - Cortical actin patches are dynamic structures required for endocytosis in yeast [1]. Recent studies have shown that components of cortical patches localize to the plasma membrane in a precisely orchestrated manner, and their movements at and away from the plasma membrane may define the endocytic membrane invagination and vesicle scission events, respectively [2]. Here, through live-cell imaging, we analyze the dynamics of the highly conserved class I unconventional myosin, Myo5, which also localizes to cortical patches and is known to be involved in endocytosis and actin nucleation [3-8]. Myo5 exhibits a pattern of dynamic localization different from all cortical patch components analyzed to date. Myo5 associates with cortical patches only transiently and remains stationary during its brief cortical lifespan. The peak of Myo5 association with cortical patches immediately precedes the fast movement of Arp2/3 complex-associated structures away from the plasma membrane, thus correlating precisely with the proposed vesicle scission event. To further test the role of Myo5, we generated a temperature-sensitive mutant myo5 allele. In the myo5 mutant cells, Myo5 exhibits a significantly extended cortical lifespan as a result of a general impairment of Myo5 function, and Arp2 patches exhibit an extended slow-movement phase prior to the fast movement toward the cell interior. The myo5 mutant cells are defective in fluid-phase endocytosis and exhibit an increased number of invaginations on the membrane. Based on these results, we hypothesize that the myosin I motor protein facilitates the membrane fusion/vesicle scission event of endocytosis.
AB - Cortical actin patches are dynamic structures required for endocytosis in yeast [1]. Recent studies have shown that components of cortical patches localize to the plasma membrane in a precisely orchestrated manner, and their movements at and away from the plasma membrane may define the endocytic membrane invagination and vesicle scission events, respectively [2]. Here, through live-cell imaging, we analyze the dynamics of the highly conserved class I unconventional myosin, Myo5, which also localizes to cortical patches and is known to be involved in endocytosis and actin nucleation [3-8]. Myo5 exhibits a pattern of dynamic localization different from all cortical patch components analyzed to date. Myo5 associates with cortical patches only transiently and remains stationary during its brief cortical lifespan. The peak of Myo5 association with cortical patches immediately precedes the fast movement of Arp2/3 complex-associated structures away from the plasma membrane, thus correlating precisely with the proposed vesicle scission event. To further test the role of Myo5, we generated a temperature-sensitive mutant myo5 allele. In the myo5 mutant cells, Myo5 exhibits a significantly extended cortical lifespan as a result of a general impairment of Myo5 function, and Arp2 patches exhibit an extended slow-movement phase prior to the fast movement toward the cell interior. The myo5 mutant cells are defective in fluid-phase endocytosis and exhibit an increased number of invaginations on the membrane. Based on these results, we hypothesize that the myosin I motor protein facilitates the membrane fusion/vesicle scission event of endocytosis.
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U2 - 10.1016/j.cub.2004.08.055
DO - 10.1016/j.cub.2004.08.055
M3 - Article
C2 - 15341750
AN - SCOPUS:4644250535
VL - 14
SP - 1604
EP - 1609
JO - Current Biology
JF - Current Biology
SN - 0960-9822
IS - 17
ER -