Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Implication of the ubiquitous, highly conserved, Ca2+ sensor calmodulin (CaM) in pea seed germination has been investigated. Mass spectrometry analysis of purified CaM revealed the coexistence in seeds of three protein isoforms, diverging from each other by single amino acid substitution in the N-terminal alpha-helix. CaM was shown to be encoded by a small multigenic family, and full-length cDNAs of the three isoforms (PsCaM1, 2 and 3) were isolated to allow the design of specific primers in more divergent 5' and 3' untranslated regions. Expression studies, performed by semiquantitative RT-PCR, demonstrated differential expression patterns of the three transcripts during germination. PsCaM1 and 2 were detected at different levels in dry axes and cotyledons, and they accumulated during imbibition and prior to radicle protrusion. In contrast, PsCaM3 appeared only upon radicle protrusion, then gradually increased in both tissues. To characterise the biochemical properties of the CaM isoforms, functional analyses were conducted in vitro using recombinant Strep-tagged proteins (CaM1-ST, CaM2-ST and CaM3-ST) expressed in Escherichia coli. Gel mobility shift assays revealed that CaM1-ST exhibited a stoichiometric binding of a synthetic amphiphilic CaM kinase II peptide while CaM2-ST and CaM3-ST affinities for the same peptide were reduced. Affinity differences were also observed for CaM isoform binding to Trp-3, an idealised helical CaM-binding peptide. However, the three proteins activated in the same way the CaM-dependent pea NAD kinase. Finally, the significance of the single substitutions upon CaM interaction with its targets is discussed in a structural context.
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PMID:Differential expression and functional analysis of three calmodulin isoforms in germinating pea (Pisum sativum L.) seeds. 1244 20

Nicotinamide adenine dinucleotide phosphate (NADP) is a critical cofactor during metabolism, calcium signaling, and oxidative defense, yet how animals regulate their NADP pools in vivo and how NADP-synthesizing enzymes are regulated have long remained unknown. Here we show that expression of Nadk, an NAD(+) kinase-encoding gene, governs NADP biosynthesis in vivo and is essential for development in Xenopus frog embryos. Unexpectedly, we found that embryonic Nadk expression is dynamic, showing cell type-specific up-regulation during both frog and sea urchin embryogenesis. We analyzed the NAD kinases (NADKs) of a variety of deuterostome animals, finding two conserved internal domains forming a catalytic core but a highly divergent N terminus. One type of N terminus (found in basal species such as the sea urchin) mediates direct catalytic activation of NADK by Ca(2+)/calmodulin (CaM), whereas the other (typical for vertebrates) is phosphorylated by a CaM kinase-dependent mechanism. This work indicates that animal NADKs govern NADP biosynthesis in vivo and are regulated by evolutionarily divergent and conserved CaM-dependent mechanisms.
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PMID:NAD kinase controls animal NADP biosynthesis and is modulated via evolutionarily divergent calmodulin-dependent mechanisms. 2560 6