TY - JOUR
T1 - Differentiation- and stress-dependent nuclear cytoplasmic redistribution of myopodin, a novel actin-bundling protein
AU - Weins, Astrid
AU - Schwarz, Karin
AU - Faul, Christian
AU - Barisoni, Laura
AU - Linke, Wolfgang A.
AU - Mundel, Peter
N1 - Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
PY - 2001/10/29
Y1 - 2001/10/29
N2 - We report the cloning and functional characterization of myopodin, the second member of the synaptopodin gene family. Myopodin shows no significant homology to any known protein except synaptopodin. Northern blot analysis resulted in a 3.6-kb transcript for mouse skeletal and heart muscle. Western blots showed an 80-kD signal for skeletal and a 95-kD signal for heart muscle. Myopodin contains one PPXY motif and multiple PXXP motifs. Myopodin colocalizes with alpha-actinin and is found at the Z-disc as shown by immunogold electron microscopy. In myoblasts, myopodin shows preferential nuclear localization. During myotube differentiation, myopodin binds to stress fibers in a punctuated pattern before incorporation into the Z-disc. Myopodin can directly bind to actin and contains a novel actin binding site in the center of the protein. Myopodin has actin-bundling activity as shown by formation of latrunculin-A-sensitive cytosolic actin bundles and nuclear actin loops in transfected cells expressing green fluorescent protein-myopodin. Under stress conditions, myopodin accumulates in the nucleus and is depleted from the cytoplasm. Nuclear export of myopodin is sensitive to leptomycin B, despite the absence of a classical nuclear export sequence. We propose a dual role for myopodin as a structural protein also participating in signaling pathways between the Z-disc and the nucleus.
AB - We report the cloning and functional characterization of myopodin, the second member of the synaptopodin gene family. Myopodin shows no significant homology to any known protein except synaptopodin. Northern blot analysis resulted in a 3.6-kb transcript for mouse skeletal and heart muscle. Western blots showed an 80-kD signal for skeletal and a 95-kD signal for heart muscle. Myopodin contains one PPXY motif and multiple PXXP motifs. Myopodin colocalizes with alpha-actinin and is found at the Z-disc as shown by immunogold electron microscopy. In myoblasts, myopodin shows preferential nuclear localization. During myotube differentiation, myopodin binds to stress fibers in a punctuated pattern before incorporation into the Z-disc. Myopodin can directly bind to actin and contains a novel actin binding site in the center of the protein. Myopodin has actin-bundling activity as shown by formation of latrunculin-A-sensitive cytosolic actin bundles and nuclear actin loops in transfected cells expressing green fluorescent protein-myopodin. Under stress conditions, myopodin accumulates in the nucleus and is depleted from the cytoplasm. Nuclear export of myopodin is sensitive to leptomycin B, despite the absence of a classical nuclear export sequence. We propose a dual role for myopodin as a structural protein also participating in signaling pathways between the Z-disc and the nucleus.
KW - Actin-binding protein
KW - Muscle differentiation
KW - Nuclear-cytoplasmic translocation
KW - Synaptopodin gene family
KW - Z-disc
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U2 - 10.1083/jcb.200012039
DO - 10.1083/jcb.200012039
M3 - Article
C2 - 11673475
AN - SCOPUS:0035851920
VL - 155
SP - 393
EP - 403
JO - Journal of Cell Biology
JF - Journal of Cell Biology
SN - 0021-9525
IS - 3
ER -