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bioRxiv · 10.1101/2022.10.12.511969

ERK3/MAPK6 dictates Cdc42/Rac1 activity and ARP2/3-dependent actin polymerization

Bogucka-Janczi, K.·Harms, G.·May-Coissieux, M.·Bentires-Alj, M.·Thiede, B.·Rajalingam, K.
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Abstract

The actin cytoskeleton is tightly controlled by RhoGTPases, actin binding proteins and nucleation-promoting factors to perform fundamental cellular functions. Here, we show that ERK3, an atypical MAPK, directly acts as a guanine nucleotide exchange factor for Cdc42 and phosphorylates the ARP3 subunit of the ARP2/3 complex at S418 to promote filopodia formation and actin polymerization, respectively. Consistently, depletion of ERK3 prevented both basal and EGF-dependent Rac1 and Cdc42 activation, maintenance of F-actin content, filopodia formation and epithelial cell migration. Further, ERK3 protein binds directly to the purified ARP2/3 complex and augments polymerization of actin in vitro. ERK3 kinase activity is required for the formation of actin-rich protrusions in mammalian cells. These findings unveil a fundamentally unique pathway employed by cells to control actin-dependent cellular functions.

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Bogucka-Janczi, K., Harms, G., May-Coissieux, M., Bentires-Alj, M., Thiede, B., Rajalingam, K.. 2022-10-13. ERK3/MAPK6 dictates Cdc42/Rac1 activity and ARP2/3-dependent actin polymerization. https://doi.org/10.1101/2022.10.12.511969

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