TY - JOUR
T1 - Lysophosphatidic acid stimulates actomyosin contraction in astrocytes
AU - Manning, Timothy J.
AU - Rosenfeld, Steven S.
AU - Sontheimer, Harald
PY - 1998/8/1
Y1 - 1998/8/1
N2 - Lysophosphatidic acid (LPA) is an extracellular signaling molecule that can enter the central nervous system following injury or diseases that disrupt the blood-brain-barrier. Using a combination of time-lapse microscopy, immunocytochemistry, and biochemical techniques, we demonstrate that LPA stimulates profound changes in astrocyte morphology that are due to effects on the actomyosin cytoskeleton. Flat astrocytes in primary culture display prominent actin stress fibers. Treatment with the myosin light chain kinase inhibitor, ML-9, causes stress fiber dissolution and dramatic morphology changes including rounding of the cell body and the formation of processes. LPA can stabilize actin stress fibers and inhibit the morphology changes in ML-9-treated cells. Furthermore, this activity is dependent upon activation of the GTP-binding protein Rho as evidenced by the ability of C3 exoenzyme, a specific inhibitor of Rho, to block the effect. Phosphorylation of the regulatory light (RLC) chain initiates conformational changes in myosin II that result in the formation of myosin filaments and the recruitment of actin into contractile stress fibers. LPA-induced stabilization of stress fibers is accompanied by increases in phosphorylation of the RLC of myosin. Furthermore, astrocytes grown on flexible silicone undergo rapid contraction in response to LPA treatment. The forces generated by these cells manifest themselves as increased wrinkling in the silicone. The observed contraction and accompanying increases in regulatory light chain phosphorylation suggest that LPA-induced signaling cascades in astrocytes regulate actin/myosin interactions.
AB - Lysophosphatidic acid (LPA) is an extracellular signaling molecule that can enter the central nervous system following injury or diseases that disrupt the blood-brain-barrier. Using a combination of time-lapse microscopy, immunocytochemistry, and biochemical techniques, we demonstrate that LPA stimulates profound changes in astrocyte morphology that are due to effects on the actomyosin cytoskeleton. Flat astrocytes in primary culture display prominent actin stress fibers. Treatment with the myosin light chain kinase inhibitor, ML-9, causes stress fiber dissolution and dramatic morphology changes including rounding of the cell body and the formation of processes. LPA can stabilize actin stress fibers and inhibit the morphology changes in ML-9-treated cells. Furthermore, this activity is dependent upon activation of the GTP-binding protein Rho as evidenced by the ability of C3 exoenzyme, a specific inhibitor of Rho, to block the effect. Phosphorylation of the regulatory light (RLC) chain initiates conformational changes in myosin II that result in the formation of myosin filaments and the recruitment of actin into contractile stress fibers. LPA-induced stabilization of stress fibers is accompanied by increases in phosphorylation of the RLC of myosin. Furthermore, astrocytes grown on flexible silicone undergo rapid contraction in response to LPA treatment. The forces generated by these cells manifest themselves as increased wrinkling in the silicone. The observed contraction and accompanying increases in regulatory light chain phosphorylation suggest that LPA-induced signaling cascades in astrocytes regulate actin/myosin interactions.
KW - Actin
KW - LPA
KW - Myosin II
KW - Myosin light chain
KW - Rho
UR - http://www.scopus.com/inward/record.url?scp=2642640420&partnerID=8YFLogxK
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U2 - 10.1002/(SICI)1097-4547(19980801)53:3<343::AID-JNR8>3.0.CO;2-A
DO - 10.1002/(SICI)1097-4547(19980801)53:3<343::AID-JNR8>3.0.CO;2-A
M3 - Article
C2 - 9698162
AN - SCOPUS:2642640420
SN - 0360-4012
VL - 53
SP - 343
EP - 352
JO - Journal of Neuroscience Research
JF - Journal of Neuroscience Research
IS - 3
ER -