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PubMed2006

FRET and colocalization analyzer--a method to validate measurements of sensitized emission FRET acquired by confocal microscopy and available as an ImageJ Plug-in.

Fluorescence resonance energy transfer (FRET) between an adequate pair of fluorophores is an indication of closer proximity than colocalization and is used by biologists to study fluorescently modified protein interactions inside cells. We present a method for visualization of FRET images acquired by confocal sensitized emission, involving excitation of the donor fluorophore and detection of the energy transfer as an emission from the acceptor fluorophore into the FRET channel. Authentic FRET signal measurements require the correction from the FRET channel of the undesired bleed-through signals (BT) resulting from both the leak-through of the donor emission and the direct acceptor emission. Our method reduces the interference of the user to a minimum by analyzing the entire image, pixel by pixel. It proposes imaging treatments and the display of control images to validate the BT calculation and the image corrections. It displays FRET images as a function of the colocalization of the two fluorescent partners. Finally, it proposes an alternative to normalization of the FRET intensities to compare FRET signal variations between samples. This method called "FRET and Colocalization Analyzer" has been implemented in a Plug-in of the freely available ImageJ software. It is particularly adapted when transient expression of the fluorescent proteins is used thereby giving very variable expression levels or when the colocalization of the two partners is varying in proportion, in amount, and in size, as a function of time. The method and program are validated using the analysis of the spatio-temporal interactions between a G-protein coupled receptor, the tachykinin NK2 receptor, and the beta-arrestin 2 as an example.

Arrestins↗
PubMed1996

Polymorphonuclear leukocytes present laminin peptides in endocytic compartments.

Rat and Human neutrophils presented cytoplasmic vacuoles immunoreactive for laminin at the electron microscopy level. Colocalization of the anti-laminin labeling with albumin-gold complexes and alkaline phosphatase activity in rat PMN suggest an endocytic nature for this compartment. Immunoblot analysis of human normal peripheral blood neutrophils revealed the presence of two laminin peptides around 100 kDa.

Animals↗
PubMed2003

Smoothelin-positive cells in human and porcine semilunar valves.

Our aim was to further characterize the interstitial cell phenotypes of normal porcine and human semilunar valves, information necessary for the design of bioengineered valves and for the understanding of valve disease processes such as aortic valve sclerosis. Existence of fibroblasts, myofibroblasts, and smooth muscle-like cells within semilunar heart valves has been established. However, the nature of the smooth muscle cell population has been controversial. We used immunochemical and western blotting methods to determine the status of smoothelin and smooth muscle alpha-actin in the valve. Our examination of valve interstitial cells confirmed the presence of terminally differentiated, contractile smooth muscle cells in situ. They were arranged in small bundles of 5-35 cells within the ventricularis or as individual cells scattered throughout the valvular layers in vivo, and were present in cells explanted from the valves in vitro. Colocalization of these proteins in semilunar heart valves was achieved with double-labeling experiments. Protein extraction, followed by coimmunoprecipitation, electrophoresis, and western blotting confirmed the immunochemical analysis and suggested that smooth muscle alpha-actin and smoothelin interact, as has been previously postulated. The presence of contractile smooth muscle within the valve may be an important factor in understanding valve pathology and in the design of tissue engineering efforts.

Animals↗
PubMed2006

A novel coiled-coil protein co-localizes and interacts with a calcium-dependent protein kinase in the common ice plant during low-humidity stress.

McCPK1 (Mesembryanthemum crystallinum calcium-dependent protein kinase 1) mRNA expression is induced transiently by salinity and water deficit stress and also McCPK1 undergoes dynamic subcellular localization changes in response to these same stresses. Here we have confirmed that low humidity is capable of causing a drastic change in McCPK1's subcellular localization. We attempted to elucidate this phenomenon by isolating components likely to be involved in this process. McCAP1 (M. crystallinum CDPK adapter protein 1) was cloned in a yeast two-hybrid screen with a constitutively active McCPK1 as bait. We show that McCPK1 and McCAP1 can interact in the yeast two-hybrid system, in vitro, and in vivo as demonstrated by coimmunoprecipitation experiments from plant extracts. However, McCAP1 does not appear to be a substrate for McCPK1. DsRed-McCAP1 and EGFP-McCPK1 fusions colocalize in epidermal cells of ice plants exposed to low humidity. McCAP1 is homologous to a family of proteins in Arabidopsis with no known function. Computational threading analysis suggests that McCAP1 is likely to be an intermediate filament protein of the cytoskeleton.

Amino Acid Sequence↗
PubMed2004

Central administration of cocaine- and amphetamine-regulated transcript increases phosphorylation of cAMP response element binding protein in corticotropin-releasing hormone-producing neurons but not in prothyrotropin-releasing hormone-producing neurons in the hypothalamic paraventricular nucleus.

Cocaine- and amphetamine-regulated transcript (CART) has an important action on hypophysiotropic thyrotropin-releasing hormone (TRH) and corticotropin-releasing hormone (CRH) neurons to regulate the hypothalamic-pituitary-thyroid and adrenal axis, respectively. To elucidate the mechanisms by which CART mediates its effect on TRH and CRH neurons, we determined whether the exogenous administration of CART into the cerebrospinal fluid (CSF) phosphorylates the transcription factor, cyclic adenosine 5'-monophosphate response element binding protein (CREB), in the nucleus of TRH and CRH neurons. CART dramatically increased the percentage of phosphoCREB (PCREB) immunolabeled cell nuclei in the hypothalamic paraventricular nucleus (PVN) in fasted as well as fed rats at 10-min postinjection, particularly in the medial parvocellular subdivision of the PVN. Double immunolabelling with CRH antiserum revealed that CART increased the number of CRH neurons containing PCREB from 10.5+/-1.2 % to 87+/-1.2% (P<0.001) in fasting animals and from 3.7+/-0.8% to 74+/-5.3% (P<0.001) in fed animals. In contrast, no significant change was observed in the percentage of proTRH neurons colocalizing with PCREB either in the fasted (11.7+/-1.85%) or fed animals (4.2+/-2.2%) as compared to their respective vehicle controls (2.5+/-1.4% and 4.6+/-1%). Ultrastructural analysis revealed that CART establishes axosomatic and axodendritic contacts with CRH neurons in the PVN. These data demonstrate a selective effect of CART to phosphorylate CREB in CRH, but not TRH neurons in the PVN. Since CART is capable of increasing the gene expression of both CRH and TRH in hypophysiotropic neurons, and CART-containing axon terminals establish synaptic relationships with hypophysiotropic CRH and TRH neurons, we propose that CART may signal to the nucleus by more than one pathway.

Animals↗
PubMed2026

Multi-omic characterization of the Hispanic/Latino blood lipidome reveals an additional locus and attenuated genetic prediction.

While lipids have been extensively investigated, genetic regulation of the circulating lipidome in diverse populations remains poorly understood. We conducted a lipidome-wide genome-wide association study (GWAS) of 830 lipid species in 2,287 Hispanic/Latino participants and performed predictive modeling across omics layers. We identified 7,593 genome-wide significant SNPs mapping to 208 genes. Conditional analysis disentangled the long-range linkage disequilibrium artifacts from the pleiotropic FADS1/2/3 cluster. Separately, we discovered an association at the GPLD1 locus for a circulating ceramide. Colocalization revealed shared genetic architecture with conventional lipids alongside distinct, species-specific pathways. Incorporating Native/Indigenous American expression quantitative trait loci (eQTLs) within a multi-omic framework uncovered 62 likely regulatory genes missed by European-centric gene expression models. Finally, genetically regulated predictive models demonstrated performance declining from transcriptomics to proteomics to lipidomics, reflecting increased distance from gene action along the molecular cascade. Our study provides a genetic landscape of lipid metabolism in a highly burdened population and highlights the challenges in predicting lipid abundance.

Hispanic/Latino population↗
PubMed1999

Augmented expression of cyclooxygenase-2 in human atherosclerotic lesions.

Cyclooxygenase-1 (Cox-1) and Cox-2 convert arachidonic acid to prostaglandin H(2), the precursor of other prostaglandins and thromboxanes, eicosanoids important in vascular pathophysiology. However, knowledge of the expression of cyclooxygenases within atherosclerotic lesions is scant. This study tested the hypothesis that human atheroma and nonatherosclerotic arteries express the two Cox isoforms differentially. Cox-1 mRNA and protein localized on endothelial and medial smooth muscle cells of normal arteries (n = 5), whereas Cox-2 expression was not detectable. In contrast, atheromatous (n = 7) lesions contained both Cox-1 and Cox-2, colocalizing mainly with macrophages of the shoulder region and lipid core periphery, whereas smooth muscle cells showed lower levels, as demonstrated by immunohistochemical and in situ hybridization analysis. Furthermore, microvascular endothelium in plaques showed notable staining for both isoforms. In accord with immunohistochemical studies, Western blot analysis of protein extracts from normal arteries revealed constitutive Cox-1, but not Cox-2, expression. Extracts of atheromatous lesions, however, contained both Cox-1 and Cox-2 protein, detected as two immunoreactive proteins of approximately 70 and 50 kd. Macrophages expressed the short form of Cox-1/-2 constitutively after several days of in vitro culture, rather than the 70-kd protein. These results shed new light on the inflammatory pathways that operate in human atheroma. In particular, the expression of Cox-2 in atheromatous, but not in unaffected, arteries has therapeutic implications, given the advent of selective Cox-2 inhibitors.

Arteriosclerosis↗
PubMedDate not supplied

Subcellular heterogeneity of mitochondrial function and dysfunction: evidence obtained by confocal imaging.

Beyond their fundamental role in energy metabolism, mitochondria perform a great variety of other important functions (e.g. in Ca2+ homeostasis, apoptosis, thermogenesis, etc.), thus suggesting their region-specific specializations and intracellular heterogeneity. Although mitochondrial functional heterogeneity has been demonstrated for several cell types, its origin and role under physiological and, in particular, pathophysiological conditions, where the extent of heterogeneity may significantly increase, remain to be elucidated. The present work thus investigated the static and dynamic heterogeneity of mitochondria and mitochondrial function in various cell types in which mitochondria may cope with specific functions including cardiomyocytes, hepatocytes and some cultured carcinoma cells. Modern confocal and two-photon fluorescent microscopy was used for the investigation and direct imaging of region-specific mitochondrial function and heterogeneity. Analysis of the autofluorescence of mitochondrial flavoproteins in hepatocytes and carcinoma cells permitted significant intracellular heterogeneity of mitochondrial redox state to be demonstrated. Comparative homogeneity and clear colocalization of mitochondrial flavoproteins, membrane potential and calcium-sensitive probes were observed in both isolated cardiomyocytes and permeabilized myocardial fibers. After ischemia reperfusion, however, or under conditions of substrate deprivation, significant heterogeneity of all these parameters was detected. Some methodological issues, mechanistic aspects, possible metabolic consequences of mitochondrial functional heterogeneity and its impact under pathological conditions are discussed.

Animals↗
PubMed1996

Molecular diagnosis of t(11;14) in mantle cell lymphoma using two-colour interphase fluorescence in situ hybridization.

t(11;14) is observed in up to 70% of mantle cell lymphoma (MCL) cases and is therefore an important diagnostic element. In routine practice, detection of t(11;14) by conventional cytogenetic techniques is hindered by the low yield and quality of tumour metaphases. Molecular techniques (Southern blot, PCR) are unable to detect a large number of 11q13 breakpoints due to scattering over distances up to 1 Mb. Using 23 MCL patients with karyotypically determined t(11;14) and eight negative controls, we have devised a two-colour interphase FISH assay for detection of the 14q + chromosome. We chose an 11q13 probe telomeric to the major 11q13 translocation cluster sites and an IGH probe centromeric of the 14q32 breakpoints. This method detected the translocation in all 23 t(11;14) positive patients, with an overall average of 60% nuclei showing colocalized signals. Widespread application of this technique will constitute an important diagnostic aid in clinical management of MCL patients. Since FISH is a convenient method for retrospective analysis of large numbers of patient specimens, this method should contribute to an accurate estimation of t(11;14) frequency in MCL and other chronic B-cell malignancies and consequently to their better nosological characterization.

Chromosomes, Human, Pair 11↗
PubMed2003

Gonadotrophin-releasing hormone drives melatonin receptor down-regulation in the developing pituitary gland.

Melatonin is produced nocturnally by the pineal gland and is a neurochemical representation of time. It regulates neuroendocrine target tissues through G-protein-coupled receptors, of which MT(1) is the predominant subtype. These receptors are transiently expressed in several fetal and neonatal tissues, suggesting distinct roles for melatonin in development and that specific developmental cues define time windows for melatonin sensitivity. We have investigated MT(1) gene expression in the rat pituitary gland. MT(1) mRNA is confined to the pars tuberalis region of the adult pituitary, but in neonates extends into the ventral pars distalis and colocalizes with luteinizing hormone beta-subunit (LH beta) expression. This accounts for the well documented transient sensitivity of rat gonadotrophs to melatonin in the neonatal period. Analysis of an upstream fragment of the rat MT(1) gene revealed multiple putative response elements for the transcription factor pituitary homeobox-1 (Pitx-1), which is expressed in the anterior pituitary from Rathke's pouch formation. A Pitx-1 expression vector potently stimulated expression of both MT(1)-luciferase and LH beta-luciferase reporter constructs in COS-7 cells. Interestingly, transcription factors that synergize with Pitx-1 to trans-activate gonadotroph-associated genes did not potentiate Pitx-1-induced MT(1)-luciferase activity. Moreover, the transcription factor, early growth response factor-1, which is induced by gonadotrophin-releasing hormone (GnRH) and trans-activates LH beta expression, attenuated Pitx-1-induced MT(1)-luciferase activity. Finally, pituitary MT(1) gene expression was 4-fold higher in hypogonadal (hpg) mice, which do not synthesize GnRH, than in their wild-type littermates. These data suggest that establishment of a mature hypothalamic GnRH input drives the postnatal decline in pituitary MT(1) gene expression.

Animals↗
PubMed2007

Identification of Rab11 as a small GTPase binding protein for the Evi5 oncogene.

The Evi5 oncogene has recently been shown to regulate the stability and accumulation of critical G(1) cell cycle factors including Emi1, an inhibitor of the anaphase-promoting complex/cyclosome, and cyclin A. Sequence analysis of the amino terminus of Evi5 reveals a Tre-2, Bub2, Cdc16 domain, which has been shown to be a binding partner and GTPase-activating protein domain for the Rab family of small Ras-like GTPases. Here we describe the identification of Evi5 as a candidate binding protein for Rab11, a GTPase that regulates intracellular transport and has specific roles in endosome recycling and cytokinesis. By yeast two-hybrid analysis, immunoprecipitation, and Biacore analysis, we demonstrate that Evi5 binds Rab11a and Rab11b in a GTP-dependent manner. However, Evi5 displays no activation of Rab11 GTPase activity in vitro. Evi5 colocalizes with Rab11 in vivo, and overexpression of Rab11 perturbs the localization of Evi5, redistributing it into Rab11-positive recycling endosomes. Interestingly, in vitro binding studies show that Rab11 effector proteins including FIP3 compete with Evi5 for binding to Rab11, suggesting a partitioning between Rab11-Evi5 and Rab11 effector complexes. Indeed, ablation of Evi5 by RNA interference causes a mislocalization of FIP3 at the abscission site during cytokinesis. These data demonstrate that Evi5 is a Rab11 binding protein and that Evi5 may cooperate with Rab11 to coordinate vesicular trafficking, cytokinesis, and cell cycle control independent of GTPase-activating protein function.

Cell Cycle↗
PubMed2006

Subcellular localization and membrane topology of the Dengue virus type 2 Non-structural protein 4B.

Dengue virus (DV) is a member of the family Flaviviridae. These positive strand RNA viruses encode a polyprotein that is processed in case of DV into 10 proteins. Although for most of these proteins distinct functions have been defined, this is less clear for the highly hydrophobic non-structural protein (NS) 4B. Despite its possible role as an antagonist of the interferon-induced antiviral response, this protein may play an additional more direct role for viral replication. In this study we determined the subcellular localization, membrane association, and membrane topology of DV NS4B. We found that NS4B resides primarily in cytoplasmic foci originating from the endoplasmic reticulum. NS4B colocalizes with NS3 and double-stranded RNA, an intermediate of viral replication, arguing that NS4B is part of the membrane-bound viral replication complex. Biochemical analysis revealed that NS4B is an integral membrane protein, and that its preceding 2K signal sequence is not required for this integration. We identified three membrane-spanning segments in the COOH-terminal part of NS4B that are sufficient to target a cytosolic marker protein to intracellular membranes. Furthermore, we established a membrane topology model of NS4B in which the NH2-terminal part of the protein is localized in the endoplasmic reticulum lumen, whereas the COOH-terminal part is composed of three trans-membrane domains with the COOH-terminal tail localized in the cytoplasm. This topology model provides a good starting point for a detailed investigation of the function of NS4B in the DV life cycle.

Amino Acid Sequence↗
PubMed2006

Expression of algal nuclear ATP synthase subunit 6 in human cells results in protein targeting to mitochondria but no assembly into ATP synthase.

Artificial transfer of mitochondrial genes to the nucleus has implications for the understanding of mitochondrial function, evolution, and human health. Therefore, we created nuclear compatible versions of human subunit a (A6) of ATP synthase, linked to a mitochondrial targeting signal. Expression and targeting of human nuclear subunit a were compared to subunit a of Chlamydomonas reinhardtii, which naturally occurs in the nucleus. Algal subunit a was targeted to mitochondria more efficiently than human nuclear subunit a variants. However, there was no evidence of improved mitochondrial function in cultured cells; on the contrary, long-term expression of algal subunit a was associated with poor survival and intolerance of growth conditions that demand heavy reliance on oxidative phosphorylation. Analysis of enriched mitochondrial membrane fractions on native gels revealed a high-molecular- weight complex containing FLAG-tagged subunit a; however, this complex did not colocalize with ATP synthase. Thus, there was no evidence of assembly of algal subunit a into holoenzyme, nor did human nuclear subunit a colocalize with ATP synthase holoenzyme. In conclusion, obstacles remain to functional expression of mitochondrial genes transferred to the nucleus.

Algal Proteins↗
PubMed1997

Mitochondrial transmission during mating in Saccharomyces cerevisiae is determined by mitochondrial fusion and fission and the intramitochondrial segregation of mitochondrial DNA.

To gain insight into the process of mitochondrial transmission in yeast, we directly labeled mitochondrial proteins and mitochondrial DNA (mtDNA) and observed their fate after the fusion of two cells. To this end, mitochondrial proteins in haploid cells of opposite mating type were labeled with different fluorescent dyes and observed by fluorescence microscopy after mating of the cells. Parental mitochondrial protein markers rapidly redistributed and colocalized throughout zygotes, indicating that during mating, parental mitochondria fuse and their protein contents intermix, consistent with results previously obtained with a single parentally derived protein marker. Analysis of the three-dimensional structure and dynamics of mitochondria in living cells with wide-field fluorescence microscopy indicated that mitochondria form a single dynamic network, whose continuity is maintained by a balanced frequency of fission and fusion events. Thus, the complete mixing of mitochondrial proteins can be explained by the formation of one continuous mitochondrial compartment after mating. In marked contrast to the mixing of parental mitochondrial proteins after fusion, mtDNA (labeled with the thymidine analogue 5-bromodeoxyuridine) remained distinctly localized to one half of the zygotic cell. This observation provides a direct explanation for the genetically observed nonrandom patterns of mtDNA transmission. We propose that anchoring of mtDNA within the organelle is linked to an active segregation mechanism that ensures accurate inheritance of mtDNA along with the organelle.

Cell Division↗
PubMed2000

Coordinated response of mammalian Rad51 and Rad52 to DNA damage.

Biochemical analysis has shown that mammalian Rad51 and Rad52 interact and synergize in DNA recombination reactions in vitro, but these proteins have not been shown to function together in response to DNA damage in vivo. By analysis of murine cells expressing murine Rad52 tagged with green fluorescent protein (GFP)-Rad52, we now show that DNA damage causes Rad51 and GFP-Rad52 to colocalize in distinct nuclear foci. Cells expressing GFP-Rad52 show both increased survival and an increased number of Rad51 foci, raising the possibility that Rad52 is limiting for repair. These observations provide evidence of coordinated function of Rad51 and Rad52 in vivo and support the hypothesis that Rad52 plays an important role in the DNA damage response in mammalian cells.

Animals↗
PubMed2001

GAT2/BGT-1 as a system responsible for the transport of gamma-aminobutyric acid at the mouse blood-brain barrier.

In this study, the gamma-aminobutyric acid (GABA) transporter at the blood-brain barrier (BBB) was identified by reverse transcription-polymerase chain reaction (RT-PCR), Western blot, and immunostaining analysis, and the transport mechanism was characterized using a conditionally immortalized mouse brain capillary endothelial cell line (TM-BBB) as an in vitro model of the BBB. gamma-Aminobutyric acid transport was studied by the cellular uptake of [ 3 H]GABA. [3H]GABA uptake by TM-BBB cells was Na (+)-, Cl(-)-, and concentration-dependent. The corresponding Michaelis-Menten constant was 679 +/- 80 micromol/L and the maximal uptake rate was 4,790 +/- 494 pmol/(mg protein x 5 minutes). [3H]GABA uptake by TM-BBB cells was significantly inhibited by betaine, beta-alanine, nipecotic acid, taurine, and quinidine, whereas probenecid, L-proline, creatine, and glycine had no effect. This type of inhibition is consistent with the predominant involvement of the GAT2/BGT-1 transporter in TM-BBB cells. RT-PCR analysis showed that GAT2/BGT-1 mRNA was expressed in TM-BBB cells, whereas Western blot analysis showed that TM-BBB cells and mouse brain capillaries express GAT2/BGT-1 protein. Moreover, confocal immunofluorescent microscopy of dual-labeled mouse brain sections demonstrated the colocalization of GAT2/BGT-1 and P-glycoprotein, a BBB-specific marker, on brain capillaries labeled with anti-GAT2/BGT-1 antibody and anti-P-glycoprotein antibody, respectively. These results are evidence that GAT2/BGT-1 is expressed at the BBB and is involved in GABA transport across the BBB.

Animals↗
PubMed2003

Phosphorylation of the potyvirus capsid protein by protein kinase CK2 and its relevance for virus infection.

We reported previously that the capsid protein (CP) of Potato virus A (PVA) is phosphorylated both in virus-infected plants and in vitro. In this study, an enzyme that phosphorylates PVA CP was identified as the protein kinase CK2. The alpha-catalytic subunit of CK2 (CK2alpha) was purified from tobacco and characterized using in-gel kinase assays and liquid chromatography-tandem mass spectrometry. The tobacco CK2alpha gene was cloned and expressed in bacterial cells. Specific antibodies were raised against the recombinant enzyme and used to demonstrate the colocalization of PVA CP and CK2alpha in infected tobacco protoplasts. A major site of CK2 phosphorylation in PVA CP was identified by a combination of mass spectrometric analysis, radioactive phosphopeptide sequencing, and mutagenesis as Thr-242 within a CK2 consensus sequence. Amino acid substitutions that affect the CK2 consensus sequence in CP were introduced into a full-length infectious cDNA clone of PVA tagged with green fluorescent protein. Analysis of the mutant viruses showed that they were defective in cell-to-cell and long-distance movement. Using in vitro assays, we demonstrated that CK2 phosphorylation inhibited the binding of PVA CP to RNA, suggesting a molecular mechanism of CK2 action. These results suggest that the phosphorylation of PVA CP by CK2 plays an important regulatory role in virus infection.

Amino Acid Sequence↗
PubMed2005

The pleckstrin homology domain-containing protein CKIP-1 is involved in regulation of cell morphology and the actin cytoskeleton and interaction with actin capping protein.

CKIP-1 is a pleckstrin homology domain-containing protein that interacts with protein kinase CK2. To elucidate the functions of CKIP-1, we generated human osteosarcoma cell lines with tetracycline-regulated expression of Flag-CKIP-1. Flag-CKIP-1 expression resulted in distinct changes in cellular morphology. Therefore, we examined the actin profile by immunofluorescence, quantitative measurement of phalloidin binding, and immunoblot analysis. These studies demonstrate that Flag-CKIP-1 expression resulted in increases in F-actin staining and protein levels of beta-actin. To elucidate the mechanisms behind the observed phenotype, we utilized tandem affinity purification to isolate CKIP-1 interacting proteins. Mass spectrometry analysis led to the identification of the actin capping protein subunits, CPalpha and CPbeta, as novel CKIP-1 interaction partners. Interactions were confirmed by coimmunoprecipitation and by colocalization. Furthermore, we demonstrate that Ser9 of CPalpha is phosphorylated by protein kinase CK2 in vitro, that CPalpha is phosphorylated in vivo, and that treatment with a CK2-specific inhibitor results in a decrease in CPalpha phosphorylation. Finally, we demonstrate that CKIP-1 and CK2 inhibit the activity of actin capping protein at the barbed ends of actin filaments. Overall, our results are consistent with CKIP-1 playing a role in the regulation of the actin cytoskeleton through its interactions with actin capping protein.

Actin Capping Proteins↗