Related Experiment Video
Updated: Jun 19, 2026
11:31
Image-Based Methods to Study Membrane Trafficking Events in Stomatal Lineage Cells
Published on: May 12, 2023
Identification of a mechanochemical checkpoint and negative feedback loop regulating branching morphogenesis
William P Daley1, Kathryn M Gulfo, Sharon J Sequeira
1Graduate program in Molecular, Cellular, Developmental, and Neural Biology, Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
Developmental Biology
|October 7, 2009
Summary
ROCK inhibition stalls submandibular salivary gland (SMG) cleft formation by blocking a mechanochemical checkpoint. Fibronectin assembly, regulated by ROCK I/myosin II, is crucial for cleft progression and epithelial proliferation.
Area of Science:
- Developmental Biology
- Cellular Mechanotransduction
- Epithelial Morphogenesis
Background:
- Submandibular salivary gland (SMG) branching morphogenesis is initiated by cleft formation.
- Actomyosin-mediated cellular contraction is a proposed mechanism for cleft formation.
- Rho-associated protein kinase (ROCK) regulates cytoskeletal contraction.
Purpose of the Study:
- To investigate the role of ROCK signaling in SMG cleft formation and progression.
- To elucidate the molecular mechanisms underlying cleft initiation and progression.
Main Methods:
- Ex vivo organ culture of mouse SMG.
- Pharmacological inhibition of ROCK and myosin II.
- ROCK isoform-specific siRNA knockdown (ROCK I and ROCK II).
- Assessment of fibronectin (FN) assembly and epithelial proliferation.
Main Results:
- ROCK inhibition, ROCK I knockdown, and myosin II inhibition stalled clefts at initiation, indicating a mechanochemical checkpoint.
- ROCK I/myosin II activity promotes localized fibronectin assembly, rendering clefts competent for progression.
- Cleft progression is driven by ROCK I/myosin II-stimulated cell proliferation and contraction, with FN assembly promoting proliferation.
- ROCK signaling also mediates a negative feedback loop to prevent further cleft initiation.
Conclusions:
- Cleft initiation and progression are distinct processes regulated by ROCK signaling.
- ROCK I and myosin II are critical for fibronectin assembly, epithelial proliferation, and cleft progression.
- A mechanochemical checkpoint involving ROCK regulates the transition from cleft initiation to progression.
Related Concept Videos
02:19Morphogenesis
Plant morphogenesis—the development of a plant’s form and structure—involves several overlapping developmental processes, including growth and cell differentiation. Precursor cells differentiate into specific cell types, which are organized into the tissues and organ systems that make up the functional plant.
03:14Notch Signaling Pathway
The Notch signaling pathway is a major intracellular signaling pathway that is highly conserved over a broad spectrum of metazoan species. It stands unique from other intracellular signaling mechanisms in animals because notch protein itself acts as the receptor as well as the primary signaling molecule.
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
03:14Notch Signaling Pathway
The Notch signaling pathway is a major intracellular signaling pathway that is highly conserved over a broad spectrum of metazoan species. It stands unique from other intracellular signaling mechanisms in animals because notch protein itself acts as the receptor as well as the primary signaling molecule.
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
The Notch gene came into the limelight in 1914 after the discovery that its mutation in Drosophila melanogaster leads to a serrated (or "notched") wing margin phenotype. It was not until 1985...
01:31Mechanism of Lamellipodia Formation
Cells migrating in response to external stimuli form lamellipodia, which are thin membrane protrusions supported by a mesh of linked, branched, or unbranched actin filaments. These actin filaments interact with myosin motor proteins, creating the dynamic actomyosin complex within the cytoskeleton. Contractility, or the ability to generate contractile stress, is inherent to the actomyosin complex. It helps cells detect the stiffness of the surrounding ECM and exert contractile force for...
01:23Negative Regulator Molecules
Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.
02:33Hedgehog Signaling Pathway
The Hedgehog gene (Hh) was first discovered due to its control of the growth of disorganized, hair-like bristles phenotype in Drosophila, much like hedgehog spines. Hh plays a crucial role in the development of organs and the maintenance of homeostasis in both invertebrates and vertebrates. However, while Drosophila has only one Hh protein, mammals have multiple functional Hedgehog proteins - Sonic (Shh), Desert (Dhh), and Indian Hedgehog (Ihh). All of these homologous proteins have adapted to...