dictyNews
Electronic Edition
Volume 46, number 28
October 9, 2020
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Abstracts
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Dictyostelium myosin 1F and myosin 1E inhibit actin waves
in a lipid-binding-dependent and motor-independent manner
Hanna Brzeska±*, Michael Bagnoli±, Edward D. Korn±1, and
Margaret A. Titus§1
From the ±Laboratory of Cell Biology, National Heart, Lung and
Blood Institute, National Institutes of Health, Bethesda, Maryland,
United States of America,
§Department of Genetics, Cell Biology and Development, University
of Minnesota, Minneapolis, Minnesota, United States of America.
Cytoskeleton, accepted 2020;77:295-302
Actin waves are F-actin-rich entities traveling on the ventral plasma
membrane by the treadmilling mechanism. Actin waves were first
discovered and are best characterized in Dictyostelium. Class I
myosins are unconventional monomeric myosins that bind lipids
through their tails. Dictyostelium has seven class I myosins, six of
these have tails (Myo1A-F) while one has a very short tail (Myo1K),
and three of them (Myo1D, Myo1E and Myo1F) bind PIP3 with high
affinity. Localization of five Dictyostelium class I myosins synchronizes
with localization and propagation of actin waves. Myo1B and Myo1C
colocalize with actin in actin waves whereas Myo1D, E and F localize
to the PIP3-rich region surrounded by actin waves. Here we studied
the effect of overexpression of the three PIP3 specific class I myosins
on actin waves. We found that ectopic expression of the short-tail
Myo1F inhibits wave formation, short-tail Myo1E has similar but
weaker inhibitory effect but long-tail Myo1D does not affect waves. A
study of Myo1F mutants shows that its membrane binding site is
absolutely required for wave inhibition but the head portion is not. The
results suggest that PIP3 specificity and the presence of two
membrane binding sites are required for inhibition of actin waves, and
thatinhibition may be caused by crosslinking of PIP3 heads groups.
submitted by:Hanna Brzeska [[log in to unmask]]
——————————————————————————————————————
Antony Durston passed away earlier this year. An obituary including
supplemental information has appeared in IJDB:
http://www.ijdb.ehu.es/web/paper/200236vn/in-memoriam-antony-durston
submitted by: Vidya Nanjundiah [[log in to unmask]]
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[End dictyNews, volume 46, number 28]
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