Characterization of a calcium- and lipid-dependent protein kinase associated with the plasma membrane of oat

Abstract

A protein kinase that is activated by calcium and lipid has been partially purified from the plasma membrane of oat roots. This protein kinase cross-reacts with four monoclonal antibodies directed against a soluble calcium-dependent protein kinase from soybean described previously [Putman-Evans, C. L., Harmon, A. C., & Cormier, M. J. (1990) Biochemistry 29, 2488-2495; Harper, J. F., Sussman, M. R., Schaller, G. E., Putnam-Evans, C., Charbonneau, H., & Harmon, A. C. (1991) Science 252, 951-954], indicating that the oat enzyme is a member of this calcium-dependent protein kinase family. Immunoblots demonstrate that the membrane-derived protein kinase is slightly larger than that observed in the cytosolic fraction of oat. Limited digestion of the membrane-derived kinase with trypsin generates a smaller water-soluble kinase that is still activated by calcium but is no longer activated by lipid. When posthomogenization proteolysis is minimized, the bulk of the immunoreactive kinase material is localized in the membrane. These results suggest that a calcium-dependent protein kinase observed in the supernatant fraction of oat extracts may originate in situ from a calcium- and lipid-dependent protein kinase which is associated with the oat plasma membrane. They further indicate that, in contrast to animal cells, the predominant calcium- and lipid-dependent protein kinase associated with the plasma membrane of plant cells has biochemical properties and amino acid sequence unlike protein kinase C.

G proteins and Ca2+-modulated protein kinases of a plasma membrane-enriched fraction and isolated eyespot apparatuses ofSpermatozopsis similis(chlorophyceae)

“…Spinach chloroplast envelope preparations were kindly provided by A. Weber (Cologne). For analyses with the monoclonal antibodies 14G5 and 12G8, which are directed against a soybean calcium-dependent protein kinase (CDPK; Harmon et al, 1987;Schaller et a]., i992), blots were incubated with a mixture of these antibodies (15 #g ml -I) for 120 min. Incubation time for the secondary antibody was 60min.…”

ZmcPKC70, a Protein Kinase C-type Enzyme from Maize

“…Earlier the presence of PKC-type activities was indicated in rice, Brassica, wheat, oat, and soybean (29,30,32,33,35,36,66), and a PKC homolog partial cDNA clone has been reported from rice callus (73). Physiological processes such as swelling of protoplasts and activation of enzymes by activators of PKC in monocots and dicots indicated the presence of such kinases in different systems (41, 64, 74 -76).…”

“…The presence of a Ca 2ϩ -and phospholipid-dependent kinase was first shown in cytosolic fractions of zucchini (28). Later such kinases were reported from oat (29) and the chloroplast envelope (30). The presence of PKC was also shown by using partially purified fractions from Amarnthus tricolor (31,32) and rice (33) by using antibodies raised against the animal enzyme.…”

Calcium-dependent protein kinase genes in corn roots

“…This could be due to the presence of other isoforms that have not been cloned yet. It should also be noted that a certain amount of CDPKs in the root tip may be associated with membrane fractions (Battey, 1990;Schaller et al, 1992 (Sumi et al, 1991;Lu et al, 1993). CDPK isoforms are known to exist in plants, but it is not dear how these isoforms are involved in cellular regulation.…”