Characterization of a eukaryotic-like protein kinase, DspB, with an atypical catalytic loop motif from Myxococcus xanthus
- 161 Downloads
Serine (Ser)/threonine (Thr) or tyrosine (Tyr) protein kinases in eukaryotes contain RDxKxxN or RDx(A/R)A(A/R)N sequences, respectively, in the catalytic loop. Myxococcus xanthus DspB is a dual-specificity kinase that contains an atypical sequence, RDVAQKN, in the catalytic loop. The DspB mutant (A165K), which contains the canonical RDxKxxN motif, had an approximate 1.3-fold increase in kinase activity toward myelin basic protein (MBP). Arginine–aspartate (RD) kinases carry a conserved Arg immediately preceding the catalytic Asp that is required for autophosphorylation of the activation loop. DspB belongs to the RD kinase family and contains one Ser residue (Ser-190) and one Thr residue (Thr-194) in the activation loop. Mutation of Ser-190 or Thr-194 to Ala did not significantly affect the kinase activity toward MBP. We previously reported that four M. xanthus eukaryotic-like kinases (EPKs) are autophosphorylated on Tyr residues. These EPKs contain six Tyr residues at homologous positions, and five of those Tyr residues, Y25, Y102, Y145, Y173, and Y205, are conserved in DspB. DspB is mainly autophosphorylated on Y145, and a Y145F mutant has reduced kinase activity, suggesting that autophosphorylation of the Tyr residue of DspB may be required for high-level kinase activity.
KeywordsMyxococcus xanthus Eukaryotic-like protein kinase Dual-specificity kinase Atypical catalytic loop RD kinase
This study was supported by Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan (25440087).
- Arora G, Sajid A, Arulanandh MD, Singhal A, Mattoo AR, Pomerantsev AP, Leppia SH, Maiti S, Singh Y (2012) Unveiling the novel dual specificity protein kinases in Bacillus anthracis: identification of the first prokaryotic dual specificity tyrosine phosphorylation-regulated kinase (DYRK)-like kinase. J Biol Chem 287:26749–26763CrossRefPubMedPubMedCentralGoogle Scholar
- Boitel B, Ortiz-Lombardía M, Durán R, Pompeo F, Cole ST, Cerveñansky C, Alzari PM (2003) PknB kinase activity is regulated by phosphorylation in two Thr residues and dephosphorylation by PstP, the cognate phospho-Ser/Thr phosphatase, in Mycobacterium tuberculosis. Mol Microbiol 49:1493–1508CrossRefPubMedGoogle Scholar
- Whitworth DE (2007) Myxobacteria: multicellularity and differentiation. ASM Press, Washington, DCGoogle Scholar