
@article {74438,
	title = {Active morphogenesis of epithelial monolayers.},
	journal = {Phys Rev E},
	volume = {100},
	year = {2019},
	month = {2019 Aug},
	pages = {022413},
	abstract = {<p>During typical early-stage embryo development, single-cell-thick tissues of tightly bound epithelial cells autonomously generate profound changes in their shape, forming the basis of organism anatomy. We report on a (covariant) active-hydrodynamic theory of such monolayer morphogenesis that is closed under its shape-changing dynamics-i.e., the degrees of freedom that encode monolayer geometry appear properly as broken-symmetry variables. In our theory, the salient physics of tissue-scale deformations emerges from a balance between the displacement and/or shear of a low-Reynolds-number embedding fluid (the "yolk") and cell-autonomous stresses, themselves a result of combining apical contractile stresses with an elastic-like mechanical response under the constraint of constant cell volume. The leading-order hydrodynamic instabilities include both passive constrained-buckling and active deformation, which can be further categorized by cell shape changes that are either "squamous to columnar" or "regular-prism to truncated-pyramid." The deformations resulting from the latter qualitatively reproduce in vivo observations of the onset of both mesoderm and posterior midgut invaginations, which take place during gastrulation in the model organism Drosophila melanogaster.</p>
},
	keywords = {Epithelium, Hydrodynamics, Models, Biological, Morphogenesis, Thermodynamics},
	issn = {2470-0053},
	doi = {10.1103/PhysRevE.100.022413},
	author = {Morris, Richard G and Rao, Madan}
}
@article {59719,
	title = {Anillin Promotes Cell Contractility by Cyclic Resetting of RhoA Residence Kinetics.},
	journal = {Dev Cell},
	volume = {49},
	year = {2019},
	month = {2019 Jun 17},
	pages = {894-906.e12},
	abstract = {<p>RhoA stimulates cell contractility by recruiting downstream effectors to the cortical plasma membrane. We now show that direct binding by anillin is required for effective signaling: this antagonizes the otherwise labile membrane association of GTP-RhoA to promote effector recruitment. However, since its binding to RhoA blocks access by other effectors, we demonstrate that anillin must also concentrate membrane phosphoinositide-4,5-P (PIP) to promote signaling. We propose and test a sequential pathway where GTP-RhoA first binds to anillin and then is retained at the membrane by PIP after it disengages from anillin. Importantly, re-binding of membrane GTP-RhoA to anillin, regulated by the cortical density of anillin, creates cycles through this pathway. These cycles repeatedly reset the dissociation kinetics of GTP-RhoA, substantially increasing its dwell time to\&nbsp;recruit effectors. Thus, anillin regulates RhoA signaling by a paradigm of kinetic scaffolding that may apply to other signals whose efficacy depends on their cortical dwell times.</p>
},
	issn = {1878-1551},
	doi = {10.1016/j.devcel.2019.04.031},
	author = {Budnar, Srikanth and Husain, Kabir B and Gomez, Guillermo A and Naghibosadat, Maedeh and Varma, Amrita and Verma, Suzie and Hamilton, Nicholas A and Morris, Richard G and Yap, Alpha S}
}
