Subcellular distribution of non-muscle myosin IIb is controlled by FILIP through Hsc70

• Published in: PloS one Vol. 12; no. 2; p. e0172257
• Main Authors: Yagi, Hideshi, Takabayashi, Tetsuji, Xie, Min-Jue, Kuroda, Kazuki, Sato, Makoto
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 24.02.2017; Public Library of Science (PLoS)
• Subjects: Actin; Actin Cytoskeleton - metabolism; Actins - chemistry; Adenosine; Adenosine triphosphatase; Adenosine Triphosphatases - metabolism; Animals; Binding; Biology; Biology and Life Sciences; Carrier Proteins - metabolism; Cells, Cultured; Cercopithecus aethiops; COS Cells; Cytoskeleton; Dendrites - metabolism; Dendritic spines; Filamins - metabolism; Gene Expression Regulation; Heat shock proteins; Hippocampus - embryology; HSC70 Heat-Shock Proteins - metabolism; Hsc70 protein; Localization; Mass Spectrometry; Mass spectroscopy; Medical research; Medicine; Mice; Mice, Inbred C57BL; Mice, Knockout; Molecular Chaperones - metabolism; Morphology; Muscle proteins; Muscles; Myosin; Neurons; Neurons - metabolism; Neurosciences; NIH 3T3 Cells; Nonmuscle Myosin Type IIB - metabolism; Physiology; Piriform Cortex - embryology; Protein Binding; Proteins; Rats; Regulation; Research and Analysis Methods; Rodents; Signal transduction; Spine; Synapses - metabolism; Triphosphatase; Japan
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0172257

The neuronal spine is a small, actin-rich dendritic or somatic protrusion that serves as the postsynaptic compartment of the excitatory synapse. The morphology of the spine reflects the activity of the synapse and is regulated by the dynamics of the actin cytoskeleton inside, which is controlled by actin binding proteins such as non-muscle myosin. Previously, we demonstrated that the subcellular localization and function of myosin IIb are regulated by its binding partner, filamin-A interacting protein (FILIP). However, how the subcellular distribution of myosin IIb is controlled by FILIP is not yet known. The objective of this study was to identify potential binding partners of FILIP that contribute to its regulation of non-muscle myosin IIb. Pull-down assays detected a 70-kDa protein that was identified by mass spectrometry to be the chaperone protein Hsc70. The binding of Hsc70 to FILIP was controlled by the adenosine triphosphatase (ATPase) activity of Hsc70. Further, FILIP bound to Hsc70 via a domain that was not required for binding non-muscle myosin IIb. Inhibition of ATPase activity of Hsc70 impaired the effect of FILIP on the subcellular distribution of non-muscle myosin IIb. Further, in primary cultured neurons, an inhibitor of Hsc70 impeded the morphological change in spines induced by FILIP. Collectively, these results demonstrate that Hsc70 interacts with FILIP to mediate its effects on non-muscle myosin IIb and to regulate spine morphology.