Cloned (Comment) | Organism |
---|---|
overexpression of FLAG-tagged full-length MHCK-B in Dictyostelium cells, in AX2, mhkB-null, and mhkA/B/C-null cell lines. Expression of GST-tagged wild-type full-length and MHCKB truncation mutants | Dictyostelium discoideum |
Protein Variants | Comment | Organism |
---|---|---|
additional information | generation of the MHCKB truncation lacking only the WD-repeat domain and of a mutant lacking the N-rich region. Cells overexpressing the MHCK mutant lacking only the WD-repeat domain exhibit cytokinesis defects and decreased myosin II assembly | Dictyostelium discoideum |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required | Dictyostelium discoideum |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + [myosin heavy-chain] | Dictyostelium discoideum | - |
ADP + [myosin heavy-chain] phosphate | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Dictyostelium discoideum | P90648 | - |
- |
Posttranslational Modification | Comment | Organism |
---|---|---|
phosphoprotein | 15 to 20 autophosphorylation sites in MHCK-B reside in the N-rich region of the kinase. Autophosphorylation of full-length MHCK-B has no effect on the kinase activity of the enzyme | Dictyostelium discoideum |
Purification (Comment) | Organism |
---|---|
recombinant GST-tagged wild-type full-length and MHCKB truncation mutants by glutathione affinity chromatography | Dictyostelium discoideum |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + MH1 peptide | - |
Dictyostelium discoideum | ADP + MH1 peeptide phosphate | - |
? | |
ATP + [myosin heavy-chain] | - |
Dictyostelium discoideum | ADP + [myosin heavy-chain] phosphate | - |
? |
Synonyms | Comment | Organism |
---|---|---|
MHCK-B | - |
Dictyostelium discoideum |
myosin heavy chain kinase B | - |
Dictyostelium discoideum |
myosin II heavy chain kinase B | - |
Dictyostelium discoideum |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
ATP | - |
Dictyostelium discoideum |
General Information | Comment | Organism |
---|---|---|
malfunction | removal of the N-rich region severely compromises MHC phosphorylation by the catalytic domain. Removal of both the N-rich and WD-repeat domains renders the catalytic domain barely able to phosphorylate MHC above detectable levels, whereas the truncation containing the N-rich region can still use MHC as a substrate, albeit at about 30% of that displayed by the full-length kinase. But the innate kinase activity of the catalytic domain is not lost upon removal of the N-rich region and/or the WD-repeat domain of MHCK-B since all three versions of MHCK-B phosphorylated MH-1 peptide to the same level | Dictyostelium discoideum |
additional information | mechanism for targeting myosin II heavy chain phosphorylation by myosin heavy chain kinase B, overview. An intrinsically unstructured, and asparagine-rich, region of a MHCK-B can mediate specific targeting of the kinase to phosphorylate myosin II heavy chain involving a direct binding interaction with myosin II filaments, while the the WD repeat domain is not absolutely required in MHCK-B substrate targeting, in contrast to isozyme MHCK-A. The N-rich region facilitates phosphorylation of MHC by binding directly to myosin II filaments | Dictyostelium discoideum |
physiological function | heavy chain phosphorylation plays a central role in regulating myosin II bipolar filament assembly in Dictyostelium | Dictyostelium discoideum |