Structure and expression of the Caenorhabditis elegans protein kinase C2 gene. Origins and regulated expression of a family of Ca2+-activated protein kinase C isoforms.
The molecular and cellular basis for concerted Ca2+/lipid signaling in Caenorhabditis elegans was investigated. A unique gene (pkc-2) and cognate cDNAs that encode six Ca2+/diacylglycerol-stimulated PKC2 isoenzymes were characterized. PKC2 polypeptides (680-717 amino acid residues) share identical catalytic, Ca2+-binding, diacylglycerol-activation and pseudosubstrate domains. However, sequences of the N- and C-terminal regions of the kinases diverge. PKC2 diversity is partly due to differential activation of transcription by distinct promoters. Each promoter precedes an adjacent exon that encodes 5'-untranslated RNA, an initiator AUG codon and a unique open reading frame. PKC2 mRNAs also incorporate one of two 3'-terminal exons via alternative splicing. Cells that are capable of receiving and propagating signals carried by Ca2+/diacylglycerol were identified by assessing activities of pkc-2 gene promoters in transgenic C. elegans and visualizing the distribution of PKC2 polypeptides via immunofluorescence. Highly-selective expression of certain PKC2 isoforms was observed in distinct subsets of neurons, intestinal and muscle cells. A low level of PKC2 isoforms is observed in embryos. When L1 larvae hatch and interact with the external environment PKC2 content increases 10-fold. Although 77- and 78-kDa PKC2 isoforms are evident throughout post-embryonic development, an 81-kDa isoform appears to be adapted for function in L1 and L2 larvae.
Islas-Trejo
A
A
Department of Molecular Pharmacology, Atran Laboratories, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Land
M
M
Tcherepanova
I
I
Freedman
J H
JH
Rubin
C S
CS
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics*; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D017238:Genes, Helminth; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000235:genetics*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011493:Protein Kinase C / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D029742:Caenorhabditis elegans Proteins; D018076:DNA, Complementary; D007527:Isoenzymes; D012333:RNA, Messenger; C579820:PKC-2 protein, C elegans; D011493:Protein Kinase C