Stochastic combinations of actin regulatory proteins are sufficient to drive filopodia formation.


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Authors
Jarsch, Iris Katharina 
Inoue, Yoshiko 
Shimo, Hanae 
Richier, Benjamin 
Abstract

Assemblies of actin and its regulators underlie the dynamic morphology of all eukaryotic cells. To understand how actin regulatory proteins work together to generate actin-rich structures such as filopodia, we analyzed the localization of diverse actin regulators within filopodia in Drosophila embryos and in a complementary in vitro system of filopodia-like structures (FLSs). We found that the composition of the regulatory protein complex where actin is incorporated (the filopodial tip complex) is remarkably heterogeneous both in vivo and in vitro. Our data reveal that different pairs of proteins correlate with each other and with actin bundle length, suggesting the presence of functional subcomplexes. This is consistent with a theoretical framework where three or more redundant subcomplexes join the tip complex stochastically, with any two being sufficient to drive filopodia formation. We provide an explanation for the observed heterogeneity and suggest that a mechanism based on multiple components allows stereotypical filopodial dynamics to arise from diverse upstream signaling pathways.

Description
Keywords
Animals, Drosophila Proteins, Drosophila melanogaster, Embryo, Nonmammalian, Fatty Acid-Binding Proteins, Pseudopodia, Xenopus, Xenopus Proteins
Journal Title
J Cell Biol
Conference Name
Journal ISSN
0021-9525
1540-8140
Volume Title
220
Publisher
Rockefeller University Press
Sponsorship
Wellcome Trust (095829/Z/11/Z)
European Research Council (281971)
Wellcome Trust (219482/Z/19/Z)
Wellcome Trust (092096/Z/10/Z)
Cancer Research Uk (None)
Wellcome Trust (098357/Z/12/Z)
Wellcome Trust (105602/Z/14/Z)
Medical Research Council (MC_PC_17230)
Herchel Smith Fellowship, Funai Foundation scholarship, Austrian Science Fund