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Query: EC:2.7.11.1 (
protein kinase
)
81,284
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
In the human lymphoblastic cell line KE 37, Northern blot analysis with cDNA probes for human regulatory subunits RII alpha RII beta of the
cAMP-dependent protein kinase
(A-kinase) type II and immunoblotting or immunoprecipitation studies with several antibodies directed against RII alpha and RII beta show that these two isoforms are expressed. The major isoform alpha is mostly cytosolic, whereas the beta isoform appears concentrated in the Golgi-centrosomal area, as judged by immunofluorescence and cell fractionation. Using a 32P-labelled RII overlay on Western blots, a 350-kDa RII-binding protein (
AKAP 350
) was specifically identified in centrosomes isolated from this cell line, whereas a Golgi fraction has previously been demonstrated to contain an 85-kDa RII-binding protein (AKAP 85).
AKAP 350
is highly insoluble and can partially be extracted from centrosomes as a complex of
AKAP 350
and RII subunit.
AKAP 350
was identified as a specific centrosomal protein previously demonstrated in the pericentriolar material. The potential significance of a specific subcellular distribution for different RII-binding proteins in nonneuronal cells is discussed.
...
PMID:A high-affinity binding protein for the regulatory subunit of cAMP-dependent protein kinase II in the centrosome of human cells. 844 Mar 20
Protein kinase A-anchoring proteins (AKAPs) localize the second messenger response to particular subcellular domains by sequestration of the type II
protein kinase A
. Previously, AKAP120 was identified from a rabbit gastric parietal cell cDNA library; however, a monoclonal antibody raised against AKAP120 labeled a 350-kDa band in Western blots of parietal cell cytosol. Recloning has now revealed that AKAP120 is a segment of a larger protein,
AKAP350
. We have now obtained a complete sequence of human gastric
AKAP350
as well as partial cDNA sequences from human lung and rabbit parietal cells. The genomic region containing
AKAP350
is found on chromosome 7q21 and is multiply spliced, producing at least three distinct
AKAP350
isoforms as well as
yotiao
, a protein associated with the N-methyl-D-aspartate receptor. Rabbit parietal cell
AKAP350
is missing a sequence corresponding to a single exon in the middle of the molecule located just after the
yotiao
homology region. Two carboxyl-terminal splice variants were also identified. Both of the major splice variants showed tissue- and cell-specific expression patterns. Immunofluorescence microscopy demonstrated that
AKAP350
was associated with centrosomes in many cell types. In polarized Madin-Darby canine kidney cells,
AKAP350
localized asymmetrically to one pole of the centrosome, and nocodazole did not alter its localization. During the cell cycle,
AKAP350
was associated with the centrosomes as well as with the cleavage furrow during anaphase and telophase. Several epithelial cell types also demonstrated noncentrosomal pools of
AKAP350
, especially parietal cells, which contained multiple cytosolic immunoreactive foci throughout the cells. The localization of
AKAP350
suggests that it may regulate centrosomal and noncentrosomal cytoskeletal systems in many different cell types.
...
PMID:AKAP350, a multiply spliced protein kinase A-anchoring protein associated with centrosomes. 991 45
A combination of
protein kinase A
type II (RII) overlay screening, database searches and PCR was used to identify a centrosomal A-kinase anchoring protein. A cDNA with an 11.7 kb open reading frame was characterized and found to correspond to 50 exons of genomic sequence on human chromosome 7q21-22. This cDNA clone encoded a 3908 amino acid protein of 453 kDa, that was designated
AKAP450
(DDBJ/EMBL/GenBank accession No. AJ131693). Sequence comparison demonstrated that the open reading frame contained a previously characterized cDNA encoding Yotiao, as well as the human homologue of AKAP120. Numerous coiled-coil structures were predicted from
AKAP450
, and weak homology to pericentrin, giantin and other structural proteins was observed. A putative RII-binding site was identified involving amino acid 2556 of
AKAP450
by mutation analysis combined with RII overlay and an amphipatic helix was predicted in this region. Immunoprecipitation of RII from RIPA-buffer extracts of HeLa cells demonstrated co-precipitation of
AKAP450
. By immunofluorecent labeling with specific antibodies it was demonstrated that
AKAP450
localized to centrosomes. Furthermore,
AKAP450
was shown to co-purify in centrosomal preparations. The observation of two mRNAs and several splice products suggests additional functions for the
AKAP450
gene.
...
PMID:Cloning and characterization of a cDNA encoding an A-kinase anchoring protein located in the centrosome, AKAP450. 1020 49
A novel 450-kDa coiled-coil protein,
CG-NAP
(centrosome and Golgi localized PKN-associated protein), was identified as a protein that interacted with the regulatory region of the protein kinase PKN, having a catalytic domain homologous to that of protein kinase C.
CG-NAP
contains two sets of putative RII (regulatory subunit of
protein kinase A
)-binding motif. Indeed,
CG-NAP
tightly bound to RIIalpha in HeLa cells. Furthermore,
CG-NAP
was coimmunoprecipitated with the catalytic subunit of protein phosphatase 2A (PP2A), when one of the B subunit of PP2A (PR130) was exogenously expressed in COS7 cells.
CG-NAP
also interacted with the catalytic subunit of protein phosphatase 1 in HeLa cells. Immunofluorescence analysis of HeLa cells revealed that
CG-NAP
was localized to centrosome throughout the cell cycle, the midbody at telophase, and the Golgi apparatus at interphase, where a certain population of PKN and RIIalpha were found to be accumulated. These data indicate that
CG-NAP
serves as a novel scaffolding protein that assembles several protein kinases and phosphatases on centrosome and the Golgi apparatus, where physiological events, such as cell cycle progression and intracellular membrane traffic, may be regulated by phosphorylation state of specific protein substrates.
...
PMID:Characterization of a novel giant scaffolding protein, CG-NAP, that anchors multiple signaling enzymes to centrosome and the golgi apparatus. 1035 86
Regulation of N-methyl-D-aspartate (NMDA) receptor activity by kinases and phosphatases contributes to the modulation of synaptic transmission. Targeting of these enzymes near the substrate is proposed to enhance phosphorylation-dependent modulation. Yotiao, an NMDA receptor-associated protein, bound the type I protein phosphatase (PP1) and the adenosine 3',5'-monophosphate (cAMP)-dependent
protein kinase
(
PKA
) holoenzyme. Anchored PP1 was active, limiting channel activity, whereas
PKA
activation overcame constitutive PP1 activity and conferred rapid enhancement of NMDA receptor currents. Hence,
yotiao
is a scaffold protein that physically attaches PP1 and
PKA
to NMDA receptors to regulate channel activity.
...
PMID:Regulation of NMDA receptors by an associated phosphatase-kinase signaling complex. 1039 Mar 70
AKAP450
(also known as
AKAP350
,
CG-NAP
or Hyperion) and pericentrin are large coiled-coil proteins found in mammalian centrosomes that serve to recruit structural and regulatory components including dynein and
protein kinase A
. We find that these proteins share a well conserved 90 amino acid domain near their C-termini that is also found in coiled-coil proteins of unknown function from Drosophila and fission yeast. Fusion of the C-terminal region from either protein to a reporter protein confers a centrosomal localization, and overexpression of the domain from
AKAP450
displaces endogenous pericentrin, suggesting recruitment to a shared site. When isolated from transfected cells the C-terminal domain of
AKAP450
was associated with calmodulin, suggesting that this protein could contribute to centrosome assembly.
...
PMID:The PACT domain, a conserved centrosomal targeting motif in the coiled-coil proteins AKAP450 and pericentrin. 1126 98
The mediation of cAMP effects by specific pools of
protein kinase A
(
PKA
) targeted to distinct subcellular domains raises the question of how inactivation of the cAMP signal is achieved locally and whether similar targeting of phosphodiesterases (PDEs) to sites of cAMP/
PKA
action could be observed. Here, we demonstrate that Sertoli cells of the testis contain an insoluble PDE4D3 isoform, which is shown by immunofluorescence to target to centrosomes. Staining of PDE4D and
PKA
shows co-localization of PDE4D with
PKA
-RIIalpha and RIIbeta in the centrosomal region. Co-precipitation of RII subunits and PDE4D3 from cytoskeletal extracts indicates a physical association of the two proteins. Distribution of PDE4D overlaps with that of the centrosomal
PKA
-anchoring protein,
AKAP450
, and
AKAP450
, PDE4D3, and
PKA
-RIIalpha co-immunoprecipitate. Finally, both PDE4D3 and
PKA
co-precipitate with a soluble fragment of
AKAP450
encompassing amino acids 1710 to 2872 when co-expressed in 293T cells. Thus, a centrosomal complex that includes PDE4D and
PKA
constitutes a novel signaling unit that may provide accurate spatio-temporal modulation of cAMP signals.
...
PMID:Phosphodiesterase 4D and protein kinase a type II constitute a signaling unit in the centrosomal area. 1128 55
Protein kinase A regulatory subunit RIIalpha is tightly bound to centrosomal structures during interphase through interaction with the A-kinase anchoring protein
AKAP450
, but dissociates and redistributes from centrosomes at mitosis. The cyclin B-p34(cdc2) kinase (CDK1) has been shown to phosphorylate RIIalpha on T54 and this has been proposed to alter the subcellular localization of RIIalpha. We have made stable transfectants from an RIIalpha-deficient leukemia cell line (Reh) that expresses either wild-type or mutant RIIalpha (RIIalpha(T54E)). When expressed, RIIalpha detaches from centrosomes at mitosis and dissociates from its centrosomal location in purified nucleus-centrosome complexes by incubation with CDK1 in vitro. By contrast, centrosomal RIIalpha(T54E) is not redistributed at mitosis, remains mostly associated with centrosomes during all phases of the cell cycle and cannot be solubilized by CDK1 in vitro. Furthermore, RIIalpha is solubilized from particular cell fractions and changes affinity for
AKAP450
in the presence of CDK1. D and V mutations of T54 also reduce affinity for the N-terminal RII-binding domain of
AKAP450
, whereas small neutral residues do not change affinity detected by surface plasmon resonance. In addition, only RIIalpha(T54E) interacts with
AKAP450
in a RIPA-soluble extract from mitotic cells. Finally, microtubule repolymerization from mitotic centrosomes of the RIIalpha(T54E) transfectant is poorer and occurs at a lower frequency than that of RIIalpha transfectants. Our results suggest that T54 phosphorylation of RIIalpha by CDK1 might serve to regulate the centrosomal association of
PKA
during the cell cycle.
...
PMID:CDK1-mediated phosphorylation of the RIIalpha regulatory subunit of PKA works as a molecular switch that promotes dissociation of RIIalpha from centrosomes at mitosis. 1159 13
Sympathetic nervous system (SNS) regulation of cardiac action potential duration (APD) is mediated by beta adrenergic receptor (betaAR) activation, which increases the slow outward potassium ion current (IKS). Mutations in two human I(KS) channel subunits, hKCNQ1 and hKCNE1, prolong APD and cause inherited cardiac arrhythmias known as LQTS (long QT syndrome). We show that betaAR modulation of I(KS) requires targeting of adenosine 3',5'-monophosphate (cAMP)-dependent
protein kinase
(
PKA
) and protein phosphatase 1 (PP1) to hKCNQ1 through the targeting protein
yotiao
. Yotiao binds to hKCNQ1 by a leucine zipper motif, which is disrupted by an LQTS mutation (hKCNQ1-G589D). Identification of the hKCNQ1 macromolecular complex provides a mechanism for SNS modulation of cardiac APD through IKS.
...
PMID:Requirement of a macromolecular signaling complex for beta adrenergic receptor modulation of the KCNQ1-KCNE1 potassium channel. 1179 44
AKAP350
is a multiply spliced family of 350-450-kDa
protein kinase A
-anchoring proteins localized to the centrosomes and the Golgi apparatus. Using AKAP350A as bait in a yeast two-hybrid screen of a rabbit parietal cell library, we have identified a novel
AKAP350
-interacting protein, transforming acidic coiled-coil-containing protein 4 (TACC4). Two-hybrid binary assays demonstrate interaction of both TACC3 and TACC4 with AKAP350A and AKAP350B. Antibodies raised to a TACC4-specific peptide sequence colocalize TACC4 with
AKAP350
at the centrosome in interphase Jurkat cells. Mitotic cell staining reveals translocation of TACC4 from the centrosome to the spindle apparatus with the majority of TACC4 at the spindle poles. Truncated TACC4 proteins lacking the
AKAP350
minimal binding domain found in the carboxyl coiled-coil region of TACC4 could no longer target to the centrosome. Amino-truncated TACC4 proteins could no longer target to the spindle apparatus. Further, overexpression of TACC4 fusion proteins that retained spindle localization in mitotic cells resulted in an increased proportion of cells present in prometaphase. We propose that
AKAP350
is responsible for sequestration of TACC4 to the centrosome in interphase, whereas a separate TACC4 domain results in functional localization of TACC4 to the spindle apparatus in mitotic cells.
...
PMID:Transforming acidic coiled-coil-containing protein 4 interacts with centrosomal AKAP350 and the mitotic spindle apparatus. 1201 14
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