Cotton fiber annexins: a potential role in the regulation of callose synthase.
Cotton fibers contain a characteristic set of proteins which interact with plasma membranes in a Ca(2+)-dependent manner. The association of these proteins with the membrane is correlated with a reduced level of UDP-glucose: (1-->3)-beta-glucan (callose) synthase activity. Analysis of the proteins released from membranes by EDTA treatment shows that the most abundant proteins comprise a family of at least three polypeptides (p34) which resemble annexins. This resemblance includes similarity in size (about 34 kDa), sequence homology, Ca(2+)-dependent precipitation or interaction with the plasma membrane, and ability to serve as a substrate for phosphorylation by endogenous protein kinase(s) which also bind to the membranes in a Ca(2+)-dependent manner. A purified fraction of these annexins binds to, and inhibits, the activity of a partially purified cotton fiber callose synthase. These findings suggest that one possible function of annexin(s) in plants is to modulate the activity and/or localization of callose synthase.
Andrawis
A
A
Department of Botany, Hebrew University, Jerusalem, Israel.
Solomon
M
M
Delmer
D P
DP
D000595:Amino Acid Sequence; D017302:Annexins / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D003368:Gossypium / Q000201:enzymology* / Q000502:physiology; D008565:Membrane Proteins; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D029702:Schizosaccharomyces pombe Proteins
D017302:Annexins; D002413:Cations, Divalent; D008565:Membrane Proteins; D010940:Plant Proteins; D029702:Schizosaccharomyces pombe Proteins; D004533:Egtazic Acid; D004492:Edetic Acid; D005964:Glucosyltransferases; C020570:1,3-beta-glucan synthase; D011494:Protein Kinases; D002118:Calcium