Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B
<p>Abstract</p> <p>Background</p> <p>Heavy chain phosphorylation plays a central role in regulating myosin II bipolar filament assembly in <it>Dictyostelium</it>, as well as in higher eukaryotic nonmuscle cells. Our previous work has demonstrated that the WD...
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BMC
2010-03-01
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| Series: | BMC Research Notes |
| Online Access: | http://www.biomedcentral.com/1756-0500/3/56 |
| _version_ | 1818541815959126016 |
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| author | Steimle Paul A Greene Jonathan Underwood Julie |
| author_facet | Steimle Paul A Greene Jonathan Underwood Julie |
| author_sort | Steimle Paul A |
| collection | DOAJ |
| description | <p>Abstract</p> <p>Background</p> <p>Heavy chain phosphorylation plays a central role in regulating myosin II bipolar filament assembly in <it>Dictyostelium</it>, as well as in higher eukaryotic nonmuscle cells. Our previous work has demonstrated that the WD-repeat domain of <it>Dictyostelium </it>myosin II heavy chain kinase B (MHCK-B), unlike its counterpart in MHCK-A, is not absolutely required for targeting of the kinase to phosphorylate MHC. Thus, we tested the hypothesis that an asparagine-rich and structurally disordered region that is unique to MHCK-B can by itself function in substrate targeting.</p> <p>Findings</p> <p>Biochemical assays comparing the activities of full-length MHCK-B, a truncation lacking only the WD-repeat domain (B-Δ-WD), and a truncation lacking both the N-rich region and the WD-repeat domain (B-Δ-N-WD) revealed that the N-rich region targets MHCK-B to phosphorylate MHC in a manner that leads to bipolar filament disassembly. This targeting is physiologically relevant since cellular over-expression of the B-Δ-WD truncation, but not the B-Δ-N-WD truncation, leads to dramatically reduced levels of myosin II filament assembly and associated defects in cytokinesis and multicellular development.</p> <p>Conclusions</p> <p>The results presented here demonstrate that an intrinsically unstructured, and asparagine-rich, region of a MHCK-B can mediate specific targeting of the kinase to phosphorylate myosin II heavy chain. This targeting involves a direct binding interaction with myosin II filaments. In terms of regulating myosin bipolar filament assembly, our results suggest that factors affecting the activity of this unique region of MHCK-B could allow for regulation of MHCK-B in a manner that is distinct from the other MHCKs in <it>Dictyostelium</it>.</p> |
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| format | Article |
| id | doaj.art-ea63a3f6d79f4f2ab98244a882ef932e |
| institution | Directory Open Access Journal |
| issn | 1756-0500 |
| language | English |
| last_indexed | 2024-12-11T22:14:07Z |
| publishDate | 2010-03-01 |
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| record_format | Article |
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| spelling | doaj.art-ea63a3f6d79f4f2ab98244a882ef932e2022-12-22T00:48:41ZengBMCBMC Research Notes1756-05002010-03-01315610.1186/1756-0500-3-56Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase BSteimle Paul AGreene JonathanUnderwood Julie<p>Abstract</p> <p>Background</p> <p>Heavy chain phosphorylation plays a central role in regulating myosin II bipolar filament assembly in <it>Dictyostelium</it>, as well as in higher eukaryotic nonmuscle cells. Our previous work has demonstrated that the WD-repeat domain of <it>Dictyostelium </it>myosin II heavy chain kinase B (MHCK-B), unlike its counterpart in MHCK-A, is not absolutely required for targeting of the kinase to phosphorylate MHC. Thus, we tested the hypothesis that an asparagine-rich and structurally disordered region that is unique to MHCK-B can by itself function in substrate targeting.</p> <p>Findings</p> <p>Biochemical assays comparing the activities of full-length MHCK-B, a truncation lacking only the WD-repeat domain (B-Δ-WD), and a truncation lacking both the N-rich region and the WD-repeat domain (B-Δ-N-WD) revealed that the N-rich region targets MHCK-B to phosphorylate MHC in a manner that leads to bipolar filament disassembly. This targeting is physiologically relevant since cellular over-expression of the B-Δ-WD truncation, but not the B-Δ-N-WD truncation, leads to dramatically reduced levels of myosin II filament assembly and associated defects in cytokinesis and multicellular development.</p> <p>Conclusions</p> <p>The results presented here demonstrate that an intrinsically unstructured, and asparagine-rich, region of a MHCK-B can mediate specific targeting of the kinase to phosphorylate myosin II heavy chain. This targeting involves a direct binding interaction with myosin II filaments. In terms of regulating myosin bipolar filament assembly, our results suggest that factors affecting the activity of this unique region of MHCK-B could allow for regulation of MHCK-B in a manner that is distinct from the other MHCKs in <it>Dictyostelium</it>.</p>http://www.biomedcentral.com/1756-0500/3/56 |
| spellingShingle | Steimle Paul A Greene Jonathan Underwood Julie Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B BMC Research Notes |
| title | Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B |
| title_full | Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B |
| title_fullStr | Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B |
| title_full_unstemmed | Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B |
| title_short | Identification of a new mechanism for targeting myosin II heavy chain phosphorylation by <it>Dictyostelium </it>myosin heavy chain kinase B |
| title_sort | identification of a new mechanism for targeting myosin ii heavy chain phosphorylation by it dictyostelium it myosin heavy chain kinase b |
| url | http://www.biomedcentral.com/1756-0500/3/56 |
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