Phosphorylation of plant actin-depolymerising factor by calmodulin-like domain protein kinase.
The actin-depolymerising factor (ADF)/cofilin group of proteins are stimulus-responsive actin-severing proteins, members of which are regulated by reversible phosphorylation. The phosphorylation site on the maize ADF, ZmADF3, is Ser-6 but the kinase responsible is unknown [Smertenko et al., Plant J. 14 (1998) 187-193]. We have partially purified the ADF kinase(s) and found it to be calcium-regulated and inhibited by N-(6-aminohexyl)-[(3)H]5-chloro-1-naphthalenesulphonamide. Immunoblotting reveals that calmodulin-like domain protein kinase(s) (CDPK) are enriched in the purified preparation and addition of anti-CDPK to in vitro phosphorylation assays results in the inhibition of ADF phosphorylation. These data strongly suggest that plant ADF is phosphorylated by CDPK(s), a class of protein kinases unique to plants and protozoa.
Allwood
E G
EG
Department of Biological Sciences, University of Durham, South Road, DH1 3LE, Durham, UK.
Smertenko
A P
AP
Hussey
P J
PJ
D051339:Actin Depolymerizing Factors; D000818:Animals; D015153:Blotting, Western; D051345:Destrin; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007887:Fabaceae / Q000201:enzymology*; D008840:Microfilament Proteins / Q000378:metabolism*; D018482:Muscle, Skeletal; D010766:Phosphorylation / Q000187:drug effects; D010768:Phosphoserine / Q000378:metabolism; D010940:Plant Proteins; D010946:Plants, Medicinal; D047428:Protein Kinase Inhibitors; D011494:Protein Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011817:Rabbits; D003313:Zea mays
D051339:Actin Depolymerizing Factors; D051345:Destrin; D004791:Enzyme Inhibitors; D008840:Microfilament Proteins; D010940:Plant Proteins; D047428:Protein Kinase Inhibitors; D010768:Phosphoserine; D011494:Protein Kinases