pentachloropseudilin and pentabromopseudilin

Primitive streak formation in the chick embryo involves large-scale highly coordinated flows of more than 100,000 cells in the epiblast. These large-scale tissue flows and deformations can be correlated with specific anisotropic cell behaviours in the forming mesendoderm through a combination of light-sheet microscopy and computational analysis. Relevant behaviours include apical contraction, elongation along the apical-basal axis followed by ingression, and asynchronous directional cell intercalation of small groups of mesendoderm cells. Cell intercalation is associated with sequential, directional contraction of apical junctions, the onset, localization and direction of which correlate strongly with the appearance of active myosin II cables in aligned apical junctions in neighbouring cells. Use of class specific myosin inhibitors and gene-specific knockdown shows that apical contraction and intercalation are myosin II dependent and also reveal critical roles for myosin I and myosin V family members in the assembly of junctional myosin II cables.

Topics: Animals; Animals, Genetically Modified; Cell Line; Cell Movement; Cell Proliferation; Cell Shape; Chick Embryo; Chickens; Gastrulation; HEK293 Cells; Heterocyclic Compounds, 4 or More Rings; Humans; Hydrocarbons, Chlorinated; Myosin Type I; Myosin Type II; Myosin Type V; Phosphorylation; Primitive Streak; Pyrroles; RNA Interference; RNA, Small Interfering

Myosin activity is crucial for many biological functions. Strong links have been established between changes in the activity of specific myosin isoforms and diseases such as cancer, cardiovascular failure, and disorders of sensory organs and the central nervous system. The modulation of specific myosin isoforms therefore holds a strong therapeutic potential. In recent work, we identified members of the marine alkaloid family of pseudilins as potent inhibitors of myosin-dependent processes. Here, we report the crystal structure of the complex between the Dictyostelium myosin 2 motor domain and 2,4-dichloro-6-(3,4,5-tribromo-1H-pyrrole-2-yl)phenol (3). Detailed comparison with previously solved structures of the myosin 2 complex with bound pentabromopseudilin (2a) or pentachloropseudilin (4a) provides insights into the molecular basis of the allosteric communication between the catalytic and the allosteric sites. Moreover, we describe the inhibitory potency for a congeneric series of halogenated pseudilins. Insight into their mode of action is gained by applying a combination of experimental and computational approaches.

Topics: Adenosine Triphosphate; Allosteric Site; Binding Sites; Catalytic Domain; Computer Simulation; Dictyostelium; Halogenation; Hydrocarbons, Chlorinated; Molecular Targeted Therapy; Myosins; Protein Binding; Protein Conformation; Pyrroles; Structure-Activity Relationship

Topics: Allosteric Regulation; Binding Sites; Catalysis; Computer Simulation; Crystallography, X-Ray; Cyclization; Dictyostelium; Hydrocarbons, Chlorinated; Hydrocarbons, Halogenated; Molecular Conformation; Myosins; Pargyline; Propylamines; Pyrroles; Silver