Actin dynamics rapidly reset chemoattractant receptor sensitivity following adaptation in neutrophils.
Neutrophils are cells of the innate immune system that hunt and kill pathogens using directed migration. This process, known as chemotaxis, requires the regulation of actin polymerization downstream of chemoattractant receptors. Reciprocal interactions between actin and intracellular signals are thought to underlie many of the sophisticated signal processing capabilities of the chemotactic cascade including adaptation, amplification and long-range inhibition. However, with existing tools, it has been difficult to discern actin's role in these processes. Most studies investigating the role of the actin cytoskeleton have primarily relied on actin-depolymerizing agents, which not only block new actin polymerization but also destroy the existing cytoskeleton. We recently developed a combination of pharmacological inhibitors that stabilizes the existing actin cytoskeleton by inhibiting actin polymerization, depolymerization and myosin-based rearrangements; we refer to these processes collectively as actin dynamics. Here, we investigated how actin dynamics influence multiple signalling responses (PI3K lipid products, calcium and Pak phosphorylation) following acute agonist addition or during desensitization. We find that stabilized actin polymer extends the period of receptor desensitization following agonist binding and that actin dynamics rapidly reset receptors from this desensitized state. Spatial differences in actin dynamics may underlie front/back differences in agonist sensitivity in neutrophils.
Department of Biophysics, Genentech Hall, University of California, , 600 16th Street, San Francisco, CA 94158, USA.
Sheel N
SN
Dandekar
Jason S
JS
Park
Grace E
GE
Peng
James J
JJ
Onuffer
Wendell A
WA
Lim
Orion D
OD
Weiner
D000199:Actins / Q000378:metabolism*; D000577:Amides / Q000494:pharmacology; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002460:Cell Line; D002633:Chemotaxis / Q000276:immunology*; D003599:Cytoskeleton / Q000187:drug effects / Q000502:physiology*; D047630:Depsipeptides / Q000494:pharmacology; D006801:Humans; D009218:Myosins / Q000187:drug effects / Q000378:metabolism*; D009504:Neutrophils / Q000276:immunology*; D010766:Phosphorylation / Q000187:drug effects; D058105:Polymerization / Q000187:drug effects; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology*; D053778:Thiazolidines / Q000494:pharmacology
D000199:Actins; D000577:Amides; D019086:Bridged Bicyclo Compounds, Heterocyclic; D047630:Depsipeptides; D011725:Pyridines; D053778:Thiazolidines; C057531:jasplakinolide; C108830:Y 27632; D009218:Myosins; C037067:latrunculin A
actin; adaptation; cell polarity; chemotaxis; neutrophil; receptor