Convergent extension movements are the main driving force of Xenopus gastrulation. A fine-tuned regulation of cadherin-mediated cell-cell adhesion is thought to be required for this process. Members of the Wnt family of extracellular glycoproteins have been shown to modulate cadherin-mediated cell-cell adhesion, convergent extension movements, and cell differentiation. Here we show that endogenous Wnt/beta-catenin signaling activity is essential for convergent extension movements due to its effect on gene expression rather than on cadherins. Our data also suggest that XLEF-1 rather than XTCF-3 is required for convergent extension movements and that XLEF-1 functions in this context in the Wnt/beta-catenin pathway to regulate Xnr-3. In contrast, activation of the Wnt/Ca2+ pathway blocks convergent extension movements, with potential regulation of the Wnt/beta-catenin pathway at two different levels. PKC, activated by the Wnt/Ca2+ pathway, blocks the Wnt/beta-catenin pathway upstream of beta-catenin and phosphorylates Dishevelled. CamKII, also activated by the Wnt/Ca2+ pathway, inhibits the Wnt/beta-catenin signaling cascade downstream of beta-catenin. Thus, an opposing cross-talk of two distinct Wnt signaling cascades regulates convergent extension movements in Xenopus.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1016/s0925-4773(01)00416-6 | DOI Listing |
Elife
January 2025
Instituto Gulbenkian de Ciência, Rua da Quinta Grande, Oeiras, Portugal.
During the trunk to tail transition the mammalian embryo builds the outlets for the intestinal and urogenital tracts, lays down the primordia for the hindlimb and external genitalia, and switches from the epiblast/primitive streak (PS) to the tail bud as the driver of axial extension. Genetic and molecular data indicate that Tgfbr1 is a key regulator of the trunk to tail transition. Tgfbr1 has been shown to control the switch of the neuromesodermal competent cells from the epiblast to the chordoneural hinge to generate the tail bud.
View Article and Find Full Text PDFBiophys J
January 2025
Department of Biology, New York University, New York, New York, 10003, USA. Electronic address:
The outer membrane is the defining structure of Gram-negative bacteria. We previously demonstrated that it is a major load-bearing component of the cell envelope and is therefore critical to the mechanical robustness of the bacterial cell. Here, to determine the key molecules and moieties within the outer membrane that underlie its contribution to cell envelope mechanics, we measured cell-envelope stiffness across several sets of mutants with altered outer-membrane sugar content, protein content, and electric charge.
View Article and Find Full Text PDFBMJ Open
January 2025
Azrieli Research Center UHC Sainte-Justine, Montreal, Quebec, Canada.
Introduction: Precision health can be described as the right intervention, at the right time, for the right person, with a focus on monitoring and maintaining health in a longitudinal approach. Despite an increasing focus on precision approaches in medicine, their application in a rehabilitation context remains unexplored. As such, a greater understanding of the current state of the literature is required, in combination with clinician, researcher and healthcare manager perspectives regarding barriers and facilitators to the practical implementation of precision rehabilitation in clinical practice.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, ON, Canada.
Lower-limb exoskeletons have demonstrated great potential for gait rehabilitation in individuals with motor impairments; however, maintaining human-exoskeleton coordination remains a challenge. The coordination problem, referred to as any mismatch or asynchrony between the user's intended trajectories and exoskeleton desired trajectories, leads to sub-optimal gait performance, particularly for individuals with residual motor ability. Here, we investigate the virtual energy regulator (VER)'s ability to generate coordinated locomotion in lower limb exoskeleton.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Chemistry, University of California, Berkeley, California 94720, United States.
Energy decomposition analysis (EDA) based on density functional theory (DFT) and self-consistent field (SCF) calculations has become widely used for understanding intermolecular interactions. This work reports a new approach to EDA for post-SCF wave functions based on closed-shell restricted second-order Mo̷ller-Plesset (MP2) together with an efficient implementation that generalizes the successful SCF-level second-generation absolutely localized molecular orbital EDA approach, ALMO-EDA-II, and improves upon MP2 ALMO-EDA-I. The new MP2 ALMO-EDA-II provides distinct energy contributions for a frozen interaction energy containing permanent electrostatics and Pauli repulsions, polarized energy-yielding induced electrostatics, dispersion-corrected energy, and the fully relaxed energy, which describes charge transfer.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!