title: Local pulsatile contractions are an intrinsic property of the myosin 2A motor in the cortical cytoskeleton of adherent cells.
abstract: The role of nonmuscle myosin 2 (NM2) pulsatile dynamics in generating contractile forces required for developmental morphogenesis has been characterized, but whether these pulsatile contractions are an intrinsic property of all actomyosin networks is not known. Here we used live-cell fluorescence imaging to show that transient, local assembly of NM2A "pulses" occurs in the cortical cytoskeleton of single adherent cells of mesenchymal, epithelial, and sarcoma origin, independent of developmental signaling cues and cell-cell or cell-ECM interactions. We show that pulses in the cortical cytoskeleton require Rho-associated kinase- or myosin light chain kinase (MLCK) activity, increases in cytosolic calcium, and NM2 ATPase activity. Surprisingly, we find that cortical cytoskeleton pulses specifically require the head domain of NM2A, as they do not occur with either NM2B or a 2B-head-2A-tail chimera. Our results thus suggest that pulsatile contractions in the cortical cytoskeleton are an intrinsic property of the NM2A motor that may mediate its role in homeostatic maintenance of tension in the cortical cytoskeleton of adherent cells.
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Baird
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Neil
authors.initials: N
authors.lastname: Billington
authors.affiliation: Genetics and Developmental Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.|College of Veterinary Medicine, Hunan Agricultural University, Changsha 410128, China.
authors.forename: Aibing
authors.initials: A
authors.lastname: Wang
authors.affiliation: Genetics and Developmental Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Adelstein
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: James R
authors.initials: JR
authors.lastname: Sellers
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Fischer
authors.affiliation: Cell Biology and Physiology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892 watermancm@nhlbi.nih.gov.
authors.forename: Clare M
authors.initials: CM
authors.lastname: Waterman
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D003599:Cytoskeleton / Q000378:metabolism / Q000502:physiology; D057054:Molecular Imaging; D009119:Muscle Contraction / Q000502:physiology; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009218:Myosins / Q000378:metabolism; D024507:Nonmuscle Myosin Type IIA / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D024501:Nonmuscle Myosin Type IIB / Q000378:metabolism / Q000502:physiology; D061848:Optical Imaging; D010766:Phosphorylation; D000072417:Protein Domains; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D000199:Actins; D000205:Actomyosin; D054460:rho-Associated Kinases; D009219:Myosin-Light-Chain Kinase; D024507:Nonmuscle Myosin Type IIA; D024501:Nonmuscle Myosin Type IIB; D009218:Myosins