Cotton fiber annexins: a potential role in the regulation of callose synthase

• Published in: The Plant journal : for cell and molecular biology 1993-06, Vol.3 (6), p.763-772
• Main Authors: Andrawis, Andrawis, Solomon, Mazal, Delmer, Deborah P.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Annexins - physiology; Calcium - metabolism; Cations, Divalent - metabolism; Cell Membrane - enzymology; Edetic Acid - pharmacology; Egtazic Acid - pharmacology; Glucosyltransferases - antagonists & inhibitors; Glucosyltransferases - metabolism; Gossypium - enzymology; Gossypium - physiology; Membrane Proteins; Molecular Sequence Data; Plant Proteins - metabolism; Protein Kinases - metabolism; Schizosaccharomyces pombe Proteins
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/j.1365-313X.1993.00763.x

SummaryCotton fibers contain a characteristic set of proteins which interact with plasma membranes in a Ca2+‐dependent manner. The association of these proteins with the membrane is correlated with a reduced level of UDP‐glucose: (1→3)‐β‐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, Ca2+‐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 Ca2+‐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.