TY - JOUR
T1 - Actin crosslinker competition and sorting drive emergent GUV size-dependent actin network architecture
AU - Bashirzadeh, Yashar
AU - Redford, Steven A.
AU - Lorpaiboon, Chatipat
AU - Groaz, Alessandro
AU - Moghimianavval, Hossein
AU - Litschel, Thomas
AU - Schwille, Petra
AU - Hocky, Glen M.
AU - Dinner, Aaron R.
AU - Liu, Allen P.
N1 - Funding Information:
We thank Giovanni Cardone and Martin Spitaler of the MPI-B Image Facility for providing FIJI image-processing tools. We thank Morgan DeSantis and Julianna Zang (University of Michigan) for help with confocal imaging using Nikon Eclipse Ti2 confocal microscope. Fluorescently labeled α-actinin and fascin were generously provided by the Kovar lab (University of Chicago). We thank Sagardip Majumder for discussions on experimental procedures and data analysis. APL acknowledges support by a Humboldt Research Fellowship for Experienced Researchers and from the National Science Foundation (1612917, 1844132, and 1817909). GMH is supported by the National Institutes of Health grant R35GM138312. ARD acknowledges support from the National Science Foundation (DMR-2011854 and EF 1935260) and the National Institutes of Health (R35GM136381). Simulation were performed on resources from the Research Computing Center at the University of Chicago.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12
Y1 - 2021/12
N2 - The proteins that make up the actin cytoskeleton can self-assemble into a variety of structures. In vitro experiments and coarse-grained simulations have shown that the actin crosslinking proteins α-actinin and fascin segregate into distinct domains in single actin bundles with a molecular size-dependent competition-based mechanism. Here, by encapsulating actin, α-actinin, and fascin in giant unilamellar vesicles (GUVs), we show that physical confinement can cause these proteins to form much more complex structures, including rings and asters at GUV peripheries and centers; the prevalence of different structures depends on GUV size. Strikingly, we found that α-actinin and fascin self-sort into separate domains in the aster structures with actin bundles whose apparent stiffness depends on the ratio of the relative concentrations of α-actinin and fascin. The observed boundary-imposed effect on protein sorting may be a general mechanism for creating emergent structures in biopolymer networks with multiple crosslinkers.
AB - The proteins that make up the actin cytoskeleton can self-assemble into a variety of structures. In vitro experiments and coarse-grained simulations have shown that the actin crosslinking proteins α-actinin and fascin segregate into distinct domains in single actin bundles with a molecular size-dependent competition-based mechanism. Here, by encapsulating actin, α-actinin, and fascin in giant unilamellar vesicles (GUVs), we show that physical confinement can cause these proteins to form much more complex structures, including rings and asters at GUV peripheries and centers; the prevalence of different structures depends on GUV size. Strikingly, we found that α-actinin and fascin self-sort into separate domains in the aster structures with actin bundles whose apparent stiffness depends on the ratio of the relative concentrations of α-actinin and fascin. The observed boundary-imposed effect on protein sorting may be a general mechanism for creating emergent structures in biopolymer networks with multiple crosslinkers.
UR - http://www.scopus.com/inward/record.url?scp=85115872856&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85115872856&partnerID=8YFLogxK
U2 - 10.1038/s42003-021-02653-6
DO - 10.1038/s42003-021-02653-6
M3 - Article
C2 - 34584211
AN - SCOPUS:85115872856
VL - 4
JO - Communications Biology
JF - Communications Biology
SN - 2399-3642
IS - 1
M1 - 1136
ER -