Actin, a globular protein found in all eukaryotic cells, is a workhorse that varies remarkably little from baker's yeast to the human body. Part of the cytoskeleton, actin assembles into networks of filaments that give the cell structural plasticity while driving many essential functions, from cell motility and division, to vesicle and organelle transport within the cell. In a groundbreaking new study in the current issue of Developmental Cell, Brandeis researchers raise the curtain on how this actin maintains just the right filament length to keep the cell healthy and happily dividing
How does the brain record a memory? Somehow our experiences and interactions can be imprinted in the mind, but exactly how neurons alter their connections to enable memory has been murky. Now a team of researchers out of Duke University say they have identified the molecular machinery that links experience with learning--and it all comes down to one microscopic motor.
Thomas Stossel and John Hartwig nab the very first actin-binding protein, find that it spurs actin fibers in vitro to coalesce into a mesh, and tie this process to what happens in vivo during phagocytosis.
The researchers explored the function of a lily (Lilium longiflorum) pollen-enriched LIM-domain-containing protein, LlLIM1, in regulating the actin dynamics in elongating pollen tube. Co-sedimentation assays revealed that the binding affinity of LlLIM1 to F-actin was simultaneously regulated both by pH and Ca(2+): LlLIM1 showed a preference for F-actin binding under low pH and low Ca(2+) concentration.
The bacterial actin homolog MreB exists as a single-copy helical cytoskeletal structure that extends between the two poles of rod-shaped bacteria. In this study, we show that equipartition of the MreB cytoskeleton into daughter cells is accomplished by division and segregation of the helical MreB array into two equivalent structures located in opposite halves of the predivisional cell.
Microbial pathogens use a variety of mechanisms to disrupt the actin cytoskeleton during infection. Vibrio parahaemolyticus (V. para) is a Gram-negative bacterium that causes gastroenteritis, and new pandemic strains are emerging throughout the world.
”NMDA receptor (NMDAR)-dependent hippocampal synaptic plasticity underlying learning and memory coordinately regulates dendritic spine structure and AMPA receptor (AMPAR) postsynaptic strength through poorly understood mechanisms. Induction of long-term depression (LTD) activates protein phosphatase 2B/calcineurin (CaN), leading to dendritic spine shrinkage through actin depolymerization and AMPAR depression through receptor dephosphorylation and internalization.“
Researchers in Child Health Research Institute South Australia demonstrate that FliI-deficient + /- mice are characterized by improved wound healing with increased epithelial migration and enhanced wound contraction.