A maize FK506-sensitive immunophilin, mzFKBP-66, is a peptidylproline cis-trans-isomerase that interacts with calmodulin and a 36-kDa cytoplasmic protein.
A member of a eukaryotic gene superfamily, encoding a peptidylproline cis-trans-isomerase (rotamase) has been isolated from a maize (Zea mays L. A69Y+) endosperm cDNA library. The maize sequence (mzFKBP-66) encodes a 66-kDa polypeptide most closely related to the subclass of rotamases which bind an immunosuppressive drug, FK506, (termed FK506-binding proteins FKBPs), and possesses four tandem copies of the FKBP-like binding domain. The sequence mzFKBP-66 is expressed ubiquitously in the maize plant, and the protein encoded is present in both cytosolic and nuclear compartments within the cell. Both the native mzFKBP-66 and a recombinant protein overexpressed in Escherichia coli showed peptidylproline cis-trans-isomerase (PPIase) activity at rates comparable to those reported for mammalian immunophilins. This activity was also sensitive to inhibition by FK506. Immunoaffinity chromatography using anti-mzFKBP66 demonstrated an association of the protein with an unknown 36-kDa polypeptide, and affinity chromatography of mzFKBP-66 on calmodulin-agarose beads indicated the presence of a calmodulin-binding site. The existence of mzFKBP-66-associated proteins suggests that plant immunophilins may act as part of multicomponent complexes, as has been shown for other representatives of this class of enzyme.
Hueros
G
G
Max-Planck-Institut für Züchtungsforschung, Köln, Germany.
Rahfeld
J
J
Salamini
F
F
Thompson
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002147:Calmodulin / Q000378:metabolism*; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism*; D018076:DNA, Complementary; D007106:Immune Sera; D008969:Molecular Sequence Data; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011817:Rabbits; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D013379:Substrate Specificity; D016559:Tacrolimus / Q000494:pharmacology*; D003313:Zea mays / Q000378:metabolism*
D002147:Calmodulin; D018076:DNA, Complementary; D007106:Immune Sera; D010940:Plant Proteins; D019696:Peptidylprolyl Isomerase; D016559:Tacrolimus