Lentil seed aquaporins form a hetero-oligomer which is phosphorylated by a Mg(2+)-dependent and Ca(2+)-regulated kinase.
In plants, aquaporins regulate the water flow through membranes during growth, development and stress responses. We have isolated two isoforms of the aquaporin family from the protein-storage vacuoles of lentil (Lens culinaris Med.) seeds. Chemical cross-linking experiments showed that both isoforms belong to the same oligomer in the membrane and are phosphorylated by a membrane-bound protein kinase. We assigned the kinase activity to a 52 kDa protein that is magnesium-dependent and calcium-regulated.
Harvengt
P
P
Laboratoire de Physiologie Végétale, CP 206/2, Faculté des Sciences, Université Libre de Bruxelles, Bld du Triomphe, B-1050 Brussels, Belgium.
Vlerick
A
A
Fuks
B
B
Wattiez
R
R
Ruysschaert
J M
JM
Homble
F
F
D000595:Amino Acid Sequence; D020346:Aquaporins / Q000737:chemistry*; D001345:Autoradiography; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D007887:Fabaceae / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007477:Ions; D008274:Magnesium / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010770:Phosphotransferases / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism; D010946:Plants, Medicinal; D011485:Protein Binding; D011487:Protein Conformation; D020033:Protein Isoforms; D011494:Protein Kinases / Q000737:chemistry*; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D013997:Time Factors
D020346:Aquaporins; D003432:Cross-Linking Reagents; D007477:Ions; D008565:Membrane Proteins; D010940:Plant Proteins; D020033:Protein Isoforms; C077491:tonoplast intrinsic protein, plant; D010770:Phosphotransferases; D011494:Protein Kinases; D008274:Magnesium; D002118:Calcium