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* Non-redundant roles for Proﬁlin2 and Proﬁlin1 during vertebrate gastrulation  Deepak K. Khadka a, Wei Liu a, Raymond Habas 

Wnt signaling pathway has emerged as a key regulator of gastrulation.

Keywords: Wnt, Non-canonical signaling, Proﬁlin1, Proﬁlin2, Daam1, Gastrulation, Morphogenesis, Xenopus 

Gastrulation is a critical morphogenetic event during vertebrate embryogenesis, and it is comprised of 
directional cell movement resulting from the polarization and reorganization of the actin cytoskeleton. The 
non-canonical Wnt signaling pathway has emerged as a key regulator of gastrulation. However, the 
molecular mechanisms by which the Wnt pathway mediates changes to the cellular actin cytoskeleton 
remains poorly deﬁned. We had previously identiﬁed the Formin protein Daam1 and an effector molecule 
XProﬁlin1 as links for Wnt-mediated cytoskeletal changes during gastrulation. We report here the identi- 
ﬁcation of XProﬁlin2 as a non-redundant and distinct effector of Daam1 for gastrulation. XProﬁlin2 interacts 
with FH1 domain of Daam1 and temporally interacts with Daam1 during gastrulation. In the Xenopus 
embryo, XProﬁlin2 is temporally expressed throughout embryogenesis and it is spatially expressed in cells 
undergoing morphogenetic movement during gastrulation. While we have previously shown XProﬁlin1 
regulates blastopore closure, overexpression or depletion of XProﬁlin2 speciﬁcally affects convergent exten- 
sion movement independent of mesodermal speciﬁcation. Speciﬁcally, we show that XProﬁlin2 modulates 
cell polarization and axial alignment of mesodermal cells undergoing gastrulation independent of XProﬁlin1. 
Together, our studies demonstrate that XProﬁlin2 and XProﬁlin1 are non-redundant effectors for Daam1 for 
non-canonical Wnt signaling and that they regulate distinct functions during vertebrate gastrulation.