Characterization of a pollen-expressed receptor-like kinase gene of Petunia inflata and the activity of its encoded kinase.
From a pollen tube cDNA library of Petunia inflata, we isolated clones encoding a protein with structural features and biochemical properties characteristic of receptor-like kinases. It was designated PRK1 for pollen receptor-like kinase 1. The cytoplasmic domain of PRK1 is highly similar to the kinase domains of other plant receptor-like kinases and contains nearly all of the conserved amino acids for serine/threonine kinases. The extracellular domain of PRK1 contains leucine-rich repeats as found in some other plant receptor-like kinases, but overall its sequence in this region does not share significant similarity. Characterization of a gene encoding PRK1 revealed the presence of two introns. During pollen development, PRK1 mRNA was first detected in anthers containing mostly binucleate microspores; it reached the highest level of mature pollen and remained at a high level in in vitro-germinated pollen tubes. The recombinant cytoplasmic domain of PRK1 autophosphorylated on serine and tyrosine, suggesting that PRK1 may be a dual-specificity kinase. Monospecific immune serum to the recombinant extracellular domain of PRK1 detected a 69-kD protein in microsomal membranes of pollen and pollen tubes. The characteristics of PRK1 suggest that it may play a role in signal transduction events during pollen development and/or pollination.
Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16802.
J H
JH
Mu
H S
HS
Lee
T H
TH
Kao
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D016384:Consensus Sequence; D017931:DNA Primers; D018076:DNA, Complementary / Q000378:metabolism; D015723:Gene Library; D017343:Genes, Plant; D006801:Humans; D008969:Molecular Sequence Data; D010940:Plant Proteins; D010944:Plants / Q000201:enzymology* / Q000235:genetics*; D011058:Pollen; D017346:Protein Serine-Threonine Kinases; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction
D017931:DNA Primers; D018076:DNA, Complementary; D010940:Plant Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; C088479:PRK1 protein, Petunia inflata; D020794:Receptor Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases