Drosophila melanogaster contains a single calmodulin gene (original) (raw)
Related papers
Calmodulin, and various ways to regulate its activity
Life Sciences, 2004
Calmodulin (CaM), the ubiquitous calcium sensor protein, is involved in almost all intracellular events. In higher vertebrates, a single protein is encoded by multiple, co-expressed genes, and the number of discrete CaM transcripts produced by a single cell is further increased by intense alternative polyadenylation signal usage. It appears most likely that the individual transcripts possess unique intracellular fates, so that this apparent redundancy multiplies the number of challenges which the cell is able to respond to. The promoter regions of the different CaM genes have been analyzed. Several putative transcription factor binding sites have been identified; however, the elements responsible for their generally strong co-expression, and even those providing different spatial and temporal control, remain to be elucidated. Moreover, a powerful posttranscriptional control mechanism is responsible for the establishment of local intracellular CaM mRNA pools. This is mainly achieved by the selective targeting of mRNAs to various cellular domains, although regulation via mRNA stability cannot be ruled out. Finally, tailoring of the CaM protein itself offers the fastest way whereby the properties of this Ca 2 + -receptor protein can be changed. Indeed, several posttranslational modifications of CaM were described earlier, but their functions are not yet understood. Here, we briefly review the regulatory levels from the gene transcription to the covalent modifications of the synthesized protein. D
Regulatory functions of calmodulin
Pharmacology & Therapeutics, 1991
Abstraet---Calmodulin is a Ca 2 + binding protein present in all eukaryotic cells that serves as the primary intracellular receptor for Ca 2+ . This 148 amino acid protein is involved in activation of more than 20 enzymes which mediate a wide variety of physiological processes. Many of these enzymes are inhibited in an intramolecular manner and the Ca 2 +--calmodulin complex relieves this inhibition. Calmodulin is essential for life as disruption of the gene in genetically tractable organisms is lethal. This protein plays important regulatory roles in cell proliferation and is required at multiple points in the cell cycle. The mechanism of enzyme activation by calmodulin and its importance in cell growth regulation are reviewed.
Novel eye-specific calmodulin methylation characterized by protein mapping inDrosophila melanogaster
PROTEOMICS, 2007
Post-translational methylation of the epsilon-amino group of lysine residues regulates a number of protein functions. Calmodulin, a key modulator of intracellular calcium signaling, is methylated on lysine 115 in many species. Although the amino acid sequence of calmodulin is highly conserved in eukaryotes, it has been shown that lysine 115 is not methylated in Drosophila calmodulin and no other methylation site has been reported. In this study, we characterized in vivo modification states of Drosophila calmodulin using proteomic methodology involving the protein mapping of microdissected Drosophila tissues on 2-D gels. We found that Drosophila calmodulin was highly expressed in methylated forms in the compound eye, whereas its methylation was hardly detected in other tissues. We identified that lysine 94 located in an EF-hand III is the methylation site in Drosophila calmodulin. The predominance of methylated calmodulin in the compound eye may imply the involvement of calmodulin in photoreceptor-specific functions through methylation.
Neuron, 1992
We have isolated a number of Drosophila cDNAs on the basis of their encoding calmodulin-binding proteins. A full-length cDNA clone corresponding to one of these genes has been cloned and sequenced. Conservation of amino acid sequence and tissue-specific expression are observed between this gene and the transient receptor potential (frp) gene. We propose the name transient recepfor potential-like (frpl) to describe this newly isolated gene. The frpl protein contains two possible calmodulin-binding sites, six transmembrane regions, and a sequence homologous to an ankyrin-like repeat. Structurally, the frpl and frp proteins resemble cation channel proteins, particularly the brain isoform of the voltage-sensitive Ca2+ channel. The identification of a protein similar to the frp gene product, yet also able to bind Ca*+/calmodulin, allows for a reinterpretation of the phenotype of the frp mutation and suggests that both genes may encode light-sensitive ion channels.
A Novel Family of Calmodulin-binding Transcription Activators in Multicellular Organisms
Journal of Biological Chemistry, 2002
Screening of cDNA expression libraries derived from plants exposed to stress, with 35 S-labeled recombinant calmodulin as a probe, revealed a new family of proteins containing a transcription activation domain and two types of DNA-binding domains designated the CG-1 domain and the transcription factor immunoglobulin domain, ankyrin repeats, and a varying number of IQ calmodulin-binding motifs. Based on domain organization and amino acid sequence comparisons, similar proteins, with the same domain organization, were identified in the genomes of other multicellular organisms including human, Drosophila, and Caenorhabditis, whereas none were found in the complete genomes of single cell eukaryotes and prokaryotes. This family of proteins was designated calmodulin-binding transcription activators (CAMTAs). Arabidopsis thaliana contains six CAMTA genes (AtCAMTA1-AtCAMTA6). The transcription activation domain of AtCAMTA1 was mapped by testing a series of protein fusions with the DNA-binding domain of the bacterial LexA transcription factor and two reporter genes fused to LexA recognition sequences in yeast cells. Two human proteins designated HsCAMTA1 and HsCAMTA2 were also shown to activate transcription in yeast using the same reporter system. Subcellular fractionation of Arabidopsis tissues revealed the presence of CAMTAs predominantly in the nucleus. Calmodulin binding assays identified a region of 25 amino acids capable of binding calmodulin with high affinity (K d ؍ 1.2 nM) in the presence of calcium. We suggest that CAMTAs comprise a conserved family of transcription factors in a wide range of multicellular eukaryotes, which possibly respond to calcium signaling by direct binding of calmodulin.
Calmodulin-binding proteins of
Biochemical and Biophysical Research Communications, 1990
Calcium is involved in the regulation of a variety of cellular processes in eucaryotic cells. For example, changes in intracellular Ca 2+ levels regulate the progression through specific stages of the cell cycle (1). Ca2+ is also involved in protein secretion and in signaling by various extracellular ligands. These processes appear to be mediated by Ca2+ fluxes within the cell. Calmodulin is a highly conserved, major Ca2+-binding protein that is found in all eucaryotic Cop?tright 0 1990 by Academic Press, Inc. All rights of reproduction in any form reserved.
2012
Background: Calmodulin is a Ca2+ binding protein and a major regulator of multiple signaling pathways. Results: Inactivation of the Ca2+ binding sites in the N- and C-terminal lobe of CaM affects cell viability differentially. Conclusion: Ca2+ binding to CaM is required for vertebrate cell survival. Significance: A novel vertebrate knock-out/knock-in system for studying the function of CaM is described. Calmodulin (CaM) was shown to be essential for survival of lower eukaryotes by gene deletion experiments. So far, no CaM gene deletion was reported in higher eukaryotes. In vertebrates, CaM is expressed from several genes, which encode an identical protein, making it difficult to generate a model system to study the effect of CaM gene deletion. Here, we present a novel genetic system based on the chicken DT40 cell line, in which the two functional CaM genes were deleted and one allele replaced with a CaM transgene that can be artificially regulated. We show that CaM is essential for ...