Dataset Information

Molecular evolution of A-kinase anchoring protein (AKAP)-7: implications in comparative PKA compartmentalization.

ABSTRACT: A-Kinase Anchoring Proteins (AKAPs) are molecular scaffolding proteins mediating the assembly of multi-protein complexes containing cAMP-dependent protein kinase A (PKA), directing the kinase in discrete subcellular locations. Splice variants from the AKAP7 gene (AKAP15/18) are vital components of neuronal and cardiac phosphatase complexes, ion channels, cardiac Ca2+ handling and renal water transport.Shown in evolutionary analyses, the formation of the AKAP7-RI/RII binding domain (required for AKAP/PKA-R interaction) corresponds to vertebrate-specific gene duplication events in the PKA-RI/RII subunits. Species analyses of AKAP7 splice variants shows the ancestral AKAP7 splice variant is AKAP7?, while the ancestral long form AKAP7 splice variant is AKAP7?. Multi-species AKAP7 gene alignments, show the recent formation of AKAP7? occurs with the loss of native AKAP7? in rats and basal primates. AKAP7 gene alignments and two dimensional Western analyses indicate that AKAP7? is produced from an internal translation-start site that is present in the AKAP7? cDNA of mice and humans but absent in rats. Immunofluorescence analysis of AKAP7 protein localization in both rat and mouse heart suggests AKAP7? replaces AKAP7? at the cardiac sarcoplasmic reticulum in species other than rat. DNA sequencing identified Human AKAP7? insertion-deletions (indels) that promote the production of AKAP7? instead of AKAP7?.This AKAP7 molecular evolution study shows that these vital scaffolding proteins developed in ancestral vertebrates and that independent mutations in the AKAP7 genes of rodents and early primates has resulted in the recent formation of AKAP7?, a splice variant of likely lesser importance in humans than currently described.

SUBMITTER: Johnson KR

PROVIDER: S-EPMC3508976 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Molecular evolution of A-kinase anchoring protein (AKAP)-7: implications in comparative PKA compartmentalization.

Johnson Keven R KR Nicodemus-Johnson Jessie J Carnegie Graeme K GK Danziger Robert S RS

BMC evolutionary biology 20120726

<h4>Background</h4>A-Kinase Anchoring Proteins (AKAPs) are molecular scaffolding proteins mediating the assembly of multi-protein complexes containing cAMP-dependent protein kinase A (PKA), directing the kinase in discrete subcellular locations. Splice variants from the AKAP7 gene (AKAP15/18) are vital components of neuronal and cardiac phosphatase complexes, ion channels, cardiac Ca2+ handling and renal water transport.<h4>Results</h4>Shown in evolutionary analyses, the formation of the AKAP7-R ...[more]

PMID: 22834419

Similar Datasets

Project description:The asexual intra-erythrocytic multiplication of the malaria parasite Plasmodium falciparum is regulated by various molecular mechanisms. In eukaryotic cells, protein kinases are known to play key roles in cell cycle regulation and signaling pathways. The activity of cAMP-dependent protein kinase (PKA) depends on A-kinase anchoring proteins (AKAPs) through protein interactions. While several components of the cAMP dependent pathway-including the PKA catalytic and regulatory subunits-have been characterized in P. falciparum, whether AKAPs are involved in this pathway remains unclear. Here, PfAKAL, an open reading frame of a potential AKAP-like protein in the P. falciparum genome was identified, and its protein partners and putative cellular functions characterized.The expression of PfAKAL throughout the erythrocytic cycle of the 3D7 strain was assessed by RT-qPCR and the presence of the corresponding protein by immunofluorescence assays. In order to study physical interactions between PfAKAL and other proteins, pull down experiments were performed using a recombinant PfAKAL protein and parasite protein extracts, or with recombinant proteins. These interactions were also tested by combining biochemical and proteomic approaches. As phosphorylation could be involved in the regulation of protein complexes, both PfAKAL and Pf14-3-3I phosphorylation was studied using a radiolabel kinase activity assay. Finally, to identify a potential function of the protein, PfAKAL sequence was aligned and structurally modeled, revealing a conserved nucleotide-binding pocket; confirmed by qualitative nucleotide binding experiments.PfAKAL is the first AKAP-like protein in P. falciparum to be identified, and shares 23 % sequence identity with the central domain of human AKAP18?. PfAKAL is expressed in mature asexual stages, merozoites and gametocytes. In spite of homology to AKAP18, biochemical and immunochemical analyses demonstrated that PfAKAL does not interact directly with the P. falciparum PKA regulatory subunit (PfPKA-R), but instead binds and colocalizes with Pf14-3-3I, which in turn interacts with PfPKA-R. In vivo, these different interactions could be regulated by phosphorylation, as PfPKA-R and Pf14-3-3I, but not PfAKAL, are phosphorylated in vitro by PKA. Interestingly, PfAKAL binds nucleotides such as AMP and cAMP, suggesting that this protein may be involved in the AMP-activated protein kinase (AMPK) pathway, or associated with phosphodiesterase activities.PfAKAL is an atypical AKAP that shares common features with human AKAP18, such as nucleotides binding. The interaction of PfAKAL with PfPKA-R could be indirectly mediated through a join interaction with Pf14-3-3I. Therefore, PfPKA localization could not depend on PfAKAL, but rather involves other partners.

Dataset Information

Molecular evolution of A-kinase anchoring protein (AKAP)-7: implications in comparative PKA compartmentalization.

Publications

Molecular evolution of A-kinase anchoring protein (AKAP)-7: implications in comparative PKA compartmentalization.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets