Comparative analysis of the cardiac structure and transcriptome of scallop and snail, perspectives on heart chamber evolution.

The evolution of a two-chambered heart, with an atrium and a ventricle, has improved heart function in both deuterostomes (vertebrates) and some protostomes (invertebrates). Although studies have examined the unique structure and function of these two chambers, molecular comparisons are few and limited to vertebrates. Here, we focus on the two-chambered protostome heart of the mollusks, offering data that may provide a better understanding of heart evolution. Specifically, we asked if the atrium and ventricle differ at the molecular level in the mollusk heart. To do so, we examined two very different species, the giant African land snail (Lissachatina fulica) and the relatively small, aquatic yesso scallop (Mizuhopecten yessoensis), with the assumption that if they exhibited commonality these similarities would likely reflect those across the phylum. We found that, although the hearts of these two species differed histologically, their cardiac gene function enrichments were similar, as revealed by transcriptomic analysis. Furthermore, the atrium and ventricle in each species had distinct gene function clusters, suggesting an evolutionary differentiation of cardiac chambers in mollusks. Finally, to explore the relationship between vertebrate and invertebrate two-chambered hearts, we compared our transcriptomic data with published data from the zebrafish, a well-studied vertebrate model with a two-chambered heart. Our analysis indicated a functional similarity of ventricular genes between the mollusks and the zebrafish, suggesting that the ventricle was differentiated to achieve the same functions in invertebrates and vertebrates. As the first such study on protostomes, our findings offered initial insights into how the two-chambered heart arose, including a possible understanding of its occurrence in both protostomes and deuterostomes. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-023-00202-0.

The effects of different endometrial preparation regimens on pregnancy outcomes in frozen-thawed embryo transfer cycles: a prospective randomized controlled study.

OBJECTIVE: An increasing number of research have emerged to compare the pregnancy outcomes between the natural cycle and the hormone replacement therapy (HRT) cycle in preparing the endometrium for frozen-thawed embryo transfer (FET), but the results are controversial. This prospective randomized controlled study was hence designed to obtain more solid evidence. MATERIALS AND METHODS: In this study, patients with regular menstrual cycle length (21-35 days) who underwent FET between January 2010 to December 2017 were recruited for this study. Upon further filtering with the selection criteria of patients being, a total of 405 patients were recruited and randomized. Finally, analysis was performed on 384 patients: 178 belonged to the natural cycle group whereas the remaining 206 were in the HRT group. The primary outcome was live birth rate, while the secondary outcomes were implantation rate, clinical pregnancy rate, early miscarriage rate, late miscarriage rate, multiple birth rate and low birth weight rate. RESULTS: The live birth rate (37.6% vs 30.1%, p = 0.119) of natural cycle group were higher than those of the hormone replacement therapy group, although the difference was not significant. The secondary outcomes were not found to differ significantly between the two groups. Nonetheless, the endometrium was found to be thicker in the natural cycle group (10.75 mm) than the HRT group (9.00 mm) (p < 0.001). CONCLUSION: No significant differences were observed between the pregnancy outcomes of the natural cycle group and the HRT group which comprised of patients with regular menstrual cycle length.

Iron overload modulates follicular microenvironment via ROS/HIF-1α/FSHR signaling.

Iron is essential for the health of reproductive system, and women with iron overload suffer from ovarian dysfunction and lack effective treatment in fertility preservation. However, the underlying mechanism of the detrimental effects of iron overload on ovarian function remains ambiguous. Here, we confirmed the excess iron in the circumjacent follicle near endometriomas, which negatively impacted the oocyte development in the affected ovaries. Further, by integrating cell line and chronic iron overload mice model, we demonstrated that iron overload can function as a ROS inducer to amplify mitochondria damage, which significantly elevated the release of cytochrome C and ultimately induced the apoptosis of granular cells. Besides, for the first time, our findings revealed that disruption of HIF-1α/FSHR/CYP19A1 signaling was critical for decreased estrogen synthesis of granular cells in response to iron overload, which can lead to apparent oocyte maldevelopment and subfertility. Overall. this study uncovered that iron overload modulated the follicular microenvironment and generated a deleterious effect on female infertility via ROS/HIF-1α/FSHR signaling. These results might provide potential implications for future clinical risk management of patients with endometrioma and hemopathy.

Profiling and Bioinformatics Analysis Revealing Differential Circular RNA Expression about Storage Lesion Regulatory in Stored Red Blood Cells.

Introduction: Circular RNA (circRNA) plays an important role in regulating metabolism of red blood cells (RBCs) and their storage lesions, but the study of how circRNA expression changes in stored RBCs has rarely been conducted. Methods: The expression change of circRNA was systemically evaluated via high-throughput sequencing on healthy RBCs on day 0, 20, and 40. And then we confirmed the reliability of the high-throughput sequencing analysis by RT-qPCR characterization on selected circRNAs. A higher parental gene enrichment was used to explore circRNA function in pathways. In addition, we deciphered a dysregulated circRNA-related ceRNAs network, and identified three circRNA-miRNA-mRNA regulatory axes related to storage lesion. Results: We identified 2,586 known and 6,216 putative novel circRNAs, more than 100 circRNAs expression levels were shifted, and the number of downregulated circRNAs was greater with longer storage time. Furthermore, a higher parental gene enrichment related to circRNA was found in pathways, including cAMP signaling pathway, ubiquitin-mediated proteolysis, apoptosis, adhesion, MAPK signaling pathway, cystine methionine metabolism, RNA degradation, RNA transport, TGF-ß, and actin regulatory pathway. hsa_circ_0007127-miR-513a-5p-SMAD4, hsa_circ_0000033-miR-19a-3p-VAMP3, and hsa_circ_0005546-miR-4720-CCND3 regulatory axes related to storage lesion was found. Conclusions: Through investigation in circRNAs profile and circRNA-miRNA-mRNA interactions, this study provides insights on stored RBC circRNA expression changes, which closely relate to the storage lesion of RBCs and their physiological functions.

Long-term GnRH agonist pretreatment before frozen embryo transfer improves pregnancy outcomes in women with adenomyosis.

RESEARCH QUESTION: Do frozen embryo transfer (FET) cycles following long-term gonadotrophin-releasing hormone agonist (GnRHa) pretreatment have better pregnancy outcomes than fresh embryo transfer cycles with long or ultra-long GnRHa protocol in these patients? DESIGN: This study included 537 women with adenomyosis divided into three groups: (Group A) FET cycles following long-term GnRHa pretreatment (192 patients); (Group B) fresh embryo transfer cycles with the ultra-long GnRHa protocol (241 patients); (Group C) fresh embryo transfer cycles with the long GnRHa protocol (104 patients). RESULTS: The total gonadotrophin dose and stimulation duration were significantly lower in Group A than in Groups B and C. The implantation and live birth rates were significantly higher in Group A than in Groups B and C. In the long-term GnRHa pretreatment and FET treatment of Group A, implantation (odds ratio [OR] 1.729, 95% confidence interval [CI] 1.073-2.788, P = 0.025), clinical pregnancy (OR 1.665, 95% CI 1.032-2.686, P = 0.037) and live birth rates (OR 1.694, 95% CI 1.045-2.746, P = 0.033) increased and miscarriage rate (OR 0.203, 95% CI 0.078-0.530, P = 0.001) decreased when compared with Group C. Comparison of Groups A and B showed that with the long-term GnRHa pretreatment, FET was a protective factor for live birth rate (OR 1.350, 95% CI 1.017-1.792, P = 0.038). CONCLUSION: FET following long-term GnRHa pretreatment has a better IVF/intracytoplasmic sperm injection outcome, and a potential benefit in terms of a lower gonadotrophin dose, and a shorter stimulation duration than fresh embryo transfer combined with a long or ultra-long GnRHa protocol.

Structural basis and mechanism of activation of two different families of G proteins by the same GPCR.

The ß1-adrenergic receptor (ß1-AR) can activate two families of G proteins. When coupled to Gs, ß1-AR increases cardiac output, and coupling to Gi leads to decreased responsiveness in myocardial infarction. By comparative structural analysis of turkey ß1-AR complexed with either Gi or Gs, we investigate how a single G-protein-coupled receptor simultaneously signals through two G proteins. We find that, although the critical receptor-interacting C-terminal α5-helices on Gαi and Gαs interact similarly with ß1-AR, the overall interacting modes between ß1-AR and G proteins vary substantially. Functional studies reveal the importance of the differing interactions and provide evidence that the activation efficacy of G proteins by ß1-AR is determined by the entire three-dimensional interaction surface, including intracellular loops 2 and 4 (ICL2 and ICL4).

Ferroptosis-Related Gene Signature Promotes Ovarian Cancer by Influencing Immune Infiltration and Invasion.

Ovarian cancer is a kind of gynecological malignancy with high mortality. Ferroptosis is a new type of iron-dependent cell death characterized by the formation of lipid peroxides and excessive accumulation of reactive oxygen species. Studies have shown that ferroptosis modulates tumor genesis, progression, and invasion, including ovarian cancer. Based on the mRNA expression data from TCGA, we construct a scoring system using consensus clustering analysis, univariate Cox regression analysis, and least absolute selection operator. Then, we systematically evaluate the relationship between score and clinical characteristics of ovarian cancer. The result from the prediction of biofunction pathways shows that score serves as an independent prognostic marker for ovarian cancer and affects tumor progression by modulating tumor metastasis. Moreover, immunocytes such as activated CD4 T cell, activated CD8 T cell, regulatory T cells, macrophage, and stromal cells, including adipocytes, epithelial cells, and fibroblast infiltrate more in the tumor microenvironment in a high-score group, indicating ferroptosis can also affect tumor immune landscape. Critically, four potentially sensitive drugs, including staurosporine, epothilone B, DMOG, and HG6-64-1 based on the scores, are predicted, and DMOG is recognized as a novel targeted drug for ovarian cancer. In general, we construct the scoring system based on ferroptosis-related genes that can predict the prognosis of ovarian cancer patients and propose that ferroptosis may affect ovarian cancer progression by mediating tumor metastasis and immune landscape. Novel drugs to target ovarian cancer are also predicted.

Structural Basis of the Activation of Heterotrimeric Gs-Protein by Isoproterenol-Bound ß1-Adrenergic Receptor.

Cardiac disease remains the leading cause of morbidity and mortality worldwide. The ß1-adrenergic receptor (ß1-AR) is a major regulator of cardiac functions and is downregulated in the majority of heart failure cases. A key physiological process is the activation of heterotrimeric G-protein Gs by ß1-ARs, leading to increased heart rate and contractility. Here, we use cryo-electron microscopy and functional studies to investigate the molecular mechanism by which ß1-AR activates Gs. We find that the tilting of α5-helix breaks a hydrogen bond between the sidechain of His373 in the C-terminal α5-helix and the backbone carbonyl of Arg38 in the N-terminal αN-helix of Gαs. Together with the disruption of another interacting network involving Gln59 in the α1-helix, Ala352 in the ß6-α5 loop, and Thr355 in the α5-helix, these conformational changes might lead to the deformation of the GDP-binding pocket. Our data provide molecular insights into the activation of G-proteins by G-protein-coupled receptors.

Baicalin inhibits growth and induces apoptosis of human osteosarcoma cells by suppressing the AKT pathway.

Osteosarcoma (OS) is one of the most prevalent types of bone malignancies with poor overall prognosis, and is reported mainly in children and adolescents. Therefore, the investigation of novel and efficient treatment strategies for patients with OS is required. Baicalin exhibits potential anticancer effects, including in OS. However, its therapeutic effect against OS and the underlying mechanisms have not been fully evaluated. In the present study, the effect of baicalin on the proliferation and apoptosis of OS cells and its underlying mechanism of AKT pathway activation was explored. Cell confluence and cell number counts revealed suppressed the growth of OS cells that were treated with baicalin. Analysis of cell viability, cell survival and cell cycle, as well as cell apoptosis revealed decreased cell viability and survival, induced cell cycle arrest and apoptosis of treated cells. Western blot analysis demonstrated significantly decreased ratios of phosphorylated-AKT/AKT and Bcl-2/Bax, and decreased protein levels of cyclin D1 and CDK4 in cells treated with baicalin. Thus, the findings from the present study suggest that the suppression of the AKT pathway may be the underlying mechanism of the antitumor effect of baicalin in OS cells.

Tensile Property of ANSI 304 Stainless Steel Weldments Subjected to Cavitation Erosion Based on Treatment of Laser Shock Processing.

Tensile property was one important index of mechanical properties of ANSI 304 stainless steel laser weldments subjected to cavitation erosion (CE). Laser shock processing (LSP) was utilized to strengthen the CE resistance, and the tensile property and fracture morphology were analyzed through three replicated experiment times. Results showed tensile process of treated weldments was composed of elastic deformation, plastic deformation, and fracture. The elastic limit, elastic modulus, elongation, area reduction, and ultimate tensile strength of tensile sample after CE were higher in view of LSP. In the fracture surface, the fiber zone, radiation zone and shear lip zone were generated, and those were more obvious through LSP. The number and size of pores in the fracture surface were smaller, and the fracture surface was smoother and more uniform. The dimples were elongated along the unified direction due to effects of LSP, and the elongated direction was in agreement with the crack propagation direction. Their distribution and shape were uniform with deeper depth. It could be reflected that the tensile property was improved by LSP and the CE resistance was also enhanced.

Structural Insights into the Induced-fit Inhibition of Fascin by a Small-Molecule Inhibitor.

Tumor metastasis is responsible for ~90% of all cancer deaths. One of the key steps of tumor metastasis is tumor cell migration and invasion. Filopodia are cell surface extensions that are critical for tumor cell migration. Fascin protein is the main actin-bundling protein in filopodia. Small-molecule fascin inhibitors block tumor cell migration, invasion, and metastasis. Here we present the structural basis for the mechanism of action of these small-molecule fascin inhibitors. X-ray crystal structural analysis of a complex of fascin and a fascin inhibitor shows that binding of the fascin inhibitor to the hydrophobic cleft between the domains 1 and 2 of fascin induces a ~35o rotation of domain 1, leading to the distortion of both the actin-binding sites 1 and 2 on fascin. Furthermore, the crystal structures of an inhibitor alone indicate that the conformations of the small-molecule inhibitors are dynamic. Mutations of the inhibitor-interacting residues decrease the sensitivity of fascin to the inhibitors. Our studies provide structural insights into the molecular mechanism of fascin protein function as well as the action of small-molecule fascin inhibitors.

G-Protein Gα13 Functions with Abl Kinase to Regulate Actin Cytoskeletal Reorganization.

Heterotrimeric G-proteins are essential cellular signal transducers. One of the G-proteins, Gα13, is critical for actin cytoskeletal reorganization, cell migration, cell proliferation, and apoptosis. Previously, we have shown that Gα13 is essential for both G-protein-coupled receptor and receptor tyrosine kinase-induced actin cytoskeletal reorganization such as dynamic dorsal ruffle turnover and cell migration. However, the mechanism by which Gα13 signals to actin cytoskeletal reorganization is not completely understood. Here we show that Gα13 directly interacts with Abl tyrosine kinase, which is a critical regulator of actin cytoskeleton. This interaction is critical for Gα13-induced dorsal ruffle turnover, endothelial cell remodeling, and cell migration. Our data uncover a new molecular signaling pathway by which Gα13 controls actin cytoskeletal reorganization.

Improving fascin inhibitors to block tumor cell migration and metastasis.

Tumor metastasis is the major cause of mortality of cancer patients, being responsible for ∼90% of all cancer deaths. One of the key steps during tumor metastasis is tumor cell migration which requires actin cytoskeletal reorganization. Among the critical actin cytoskeletal protrusion structures are antenna-like filopodia. Fascin protein is the main actin-bundling protein in filopodia. Here we report the development of fascin-specific small-molecules that inhibit the interaction between fascin and actin. These inhibitors block the in vitro actin-binding and actin-bundling activities of fascin, tumor cell migration and tumor metastasis in mouse models. Mechanistically, these inhibitors likely occupy one of the actin-binding sites, reduce the binding of actin filaments, and thus lead to the inhibition of the bundling activity of fascin. At the cellular level, these inhibitors impair actin cytoskeletal reorganization. Our data indicate that target-specific anti-fascin agents will have great potential for treating metastatic tumors.

Targeted inhibition of fascin function blocks tumour invasion and metastatic colonization.

One of the key steps during tumour metastasis is tumour cell migration and invasion, which require actin cytoskeletal reorganization. Among the critical actin cytoskeletal protrusion structures are the filopodia, which act like cell sensory organs to communicate with the extracellular microenvironment and participate in fundamental cell functions such as cell adhesion, spreading and migration in the three-dimensional environment. Fascin is the main actin-bundling protein in filopodia. Using high-throughput screening, here we identify and characterize small molecules that inhibit the actin-bundling activity of fascin. Focusing on one such inhibitor, we demonstrate that it specifically blocks filopodial formation, tumour cell migration and invasion in vitro, and metastasis in vivo. Hence, target-specific anti-fascin agents have a therapeutic potential for cancer treatment.

Expression of Wnt and Notch signaling pathways in inflammatory bowel disease treated with mesenchymal stem cell transplantation: evaluation in a rat model.

INTRODUCTION: The purpose of this study was to investigate the expression of Wnt and Notch signaling pathway-related genes in inflammatory bowel disease (IBD) treated with mesenchymal stem cell transplantation (MSCT). METHODS: TNBS (2,4,6-trinitrobenzene sulfonic acid) was used to establish IBD in a rat model. Mesenchymal stem cells (MSCs) were transplanted via tail vein transfusion. Saline water was used in a control group. The expression of Wnt and Notch main signaling molecules was screened by gene chips and verified by quantitative reverse transcription-polymerase chain reaction in the IBD rat model on day 14 and day 28 after transplantation. RESULTS: The IBD rat models were successfully established and MSCs were transplanted into those models. Genome-wide expression profile chips identified a total of 388 differentially expressive genes, of which 191 were upregulated and 197 were downregulated in the MSC-transplanted group in comparison with the IBD control group. Real-time quantitative polymerase chain reaction results showed that the level of Olfm4 mRNA expression in the IBD group (2.54±0.20) was significantly increased compared with the MSCT group (1.39±0.54) and the normal group (1.62±0.25) (P <0.05). The Wnt3a mRNA was more highly expressed in IBD rats (2.92±0.94) and decreased in MSCT rats (0.17±0.63, P <0.05). The expression of GSK-3ß mRNA was decreased in the setting of inflammation (0.65±0.04 versus 1.00±0.01 in normal group, P <0.05) but returned to normal levels after MSCT (0.81±0.17). The expression of ß-catenin was observed to increase in IBD tissues (1.76±0.44) compared with normal tissues (1.00±0.01, P <0.05), but no difference was found in the MSCT group (1.12±0.36). Wnt11 declined at 14 days and returned to normal levels at 28 days in the IBD group; in comparison, a significantly lower expression was found in MSCT rats. There were no differences in the expression of Fzd3, c-myc, TCF4, and Wnt5a in inflammation, but all of those genes declined after MSCT treatment. CONCLUSIONS: The canonical Wnt and Notch signaling pathways are activated in IBD and may be suppressed by stem cell transplantation to differentiate into intestinal epithelium after MSCT. Moreover, the non-canonical Wnt signaling may be inhibited by canonical Wnt signaling in the setting of inflammation and may also be suppressed by MSCT.

Pivotal role of extended linker 2 in the activation of Gα by G protein-coupled receptor.

G protein-coupled receptors (GPCRs) relay extracellular signals mainly to heterotrimeric G-proteins (Gαßγ) and they are the most successful drug targets. The mechanisms of G-protein activation by GPCRs are not well understood. Previous studies have revealed a signal relay route from a GPCR via the C-terminal α5-helix of Gα to the guanine nucleotide-binding pocket. Recent structural and biophysical studies uncover a role for the opening or rotating of the α-helical domain of Gα during the activation of Gα by a GPCR. Here we show that ß-adrenergic receptors activate eight Gαs mutant proteins (from a screen of 66 Gαs mutants) that are unable to bind Gßγ subunits in cells. Five of these eight mutants are in the αF/Linker 2/ß2 hinge region (extended Linker 2) that connects the Ras-like GTPase domain and the α-helical domain of Gαs. This extended Linker 2 is the target site of a natural product inhibitor of Gq. Our data show that the extended Linker 2 is critical for Gα activation by GPCRs. We propose that a GPCR via its intracellular loop 2 directly interacts with the ß2/ß3 loop of Gα to communicate to Linker 2, resulting in the opening and closing of the α-helical domain and the release of GDP during G-protein activation.

A signal transducer and activator of transcription 3·Nuclear Factor κB (Stat3·NFκB) complex is necessary for the expression of fascin in metastatic breast cancer cells in response to interleukin (IL)-6 and tumor necrosis factor (TNF)-α.

IL-6 mediated activation of Stat3 is a major signaling pathway in the process of breast cancer metastasis. One important mechanism by which the IL-6/Stat3 pathway promotes metastasis is through transcriptional regulation of the actin-bundling protein fascin. In this study, we further analyzed the transcriptional regulation of the fascin gene promoter. We show that in addition to IL-6, TNF-α increases Stat3 and NFκB binding to the fascin promoter to induce its expression. We also show that NFκB is required for Stat3 recruitment to the fascin promoter in response to IL-6. Furthermore, Stat3 and NFκB form a protein complex in response to cytokine stimulation. Finally, we demonstrate that an overlapping STAT/NFκB site in a highly conserved 160-bp region of the fascin promoter is sufficient and necessary to induce transcription in response to IL-6 and TNF-α.

[Anisakis simplex larvae: infection status in marine fishes for sale in Shantou].

OBJECTIVE: To investigate the infection status of Anisakis simplex larvae in marine fishes for sale in Shantou. METHODS: Marine fishes were randomly collected from markets in Shantou City from February to December 2013, and then classified. The viscera and muscle of each fish were carefully dissected and thoroughly examined for anisakids. The larvae were examined under a light microscope. The infection rate and intensity of Anisakis simplex larvae were calculated. RESULTS: A total of 382 fish specimens belonging to 52 species were examined. 42 out of 52 species (80.8%) were found infected by A. simplex larvae. The overall infection rate reached 47.4% (181/382), and average 5.5 larvae parasitized per infected fish (995/181). The survival rate of larvae was 100%. The highest infection rate observed was 100% in Scomber australasicus (4/4), Trachurus japonicus (9/9), Decapterus maruadsi (8/8), Lutjanus lutjanus (9/9), Argyrosomus argentatus (4/4), Nibea albiflora (4/4), Nemipterus bathybius (12/12), Trachinocephalus myops (7/7) and Mene maculata (9/9), followed by 16/18 in Pneumatophorus japonicus, 6/7 in Lutjanus ophuysenii and 5/6 in Lutjanus fulvus. A. simplex larvae were not detected in 10 fish species, namely, Megalaspis cordyla, Lutjanus argentimaculatus, Lutjanus fulviflamma, Acanthopagrus australis, Acanthopagrus latus, Plectorhinchus nigrus, Dentex tumifrons, Psenopsis anomala, Scatophagus argus, and Seriola lalandi. The infection intensity was the highest in Lutjanus fulvus (21.0 per fish), followed by Trachinocephalus myops (16.7 per fish), Saurida filamentosa (14.0 per fish) and Mene maculate (10.1 per fish). The lowest infection intensity was found in Rastrelliger kanagurta, Kaiwarinus equula, Atule mate, Lutjanus russellii, Plectorhinchus cinctus, Priacanthus tayenus, Branchiostegus argentatus, Branchiostegus albus, Sphyraena pinguis, Formio niger, Trachinotus blochii, Siganus fuscescens and Choerodon azurio (less than 2 per fish). The highest infection rate (34.3%, 131/382) was found in the mesentery. The infection intensity was highest in pyloric appendage (3.5 per fish). A. simplex larvae were not found in muscle. The highest infection rate (60.2%, 74/123) was found in fishes with body weight of 100-200 g. The infection intensity was highest in fish with body weight of 301-400 g (7.8 per fish). CONCLUSION: The infection rate of A. simplex larvae is high in marine fishes from Shantou markets.

Atypical protein kinase Cλ is critical for growth factor receptor-induced dorsal ruffle turnover and cell migration.

Gα13, a member of the heterotrimeric G proteins, is critical for actin cytoskeletal reorganization and cell migration. Previously we have shown that Gα13 is essential for both G protein-coupled receptor and receptor tyrosine kinase-induced actin cytoskeletal reorganization such as dynamic dorsal ruffle turnover and cell migration. Ric-8A, a non-receptor guanine nucleotide exchange factor for some heterotrimeric G proteins, is critical for coupling receptor tyrosine kinases to Gα13. Here, we show that PDGF can induce phosphorylation of Ric-8A. Atypical protein kinase Cλ (aPKCλ) is required for Ric-8A phosphorylation. Furthermore, aPKCλ is required for PDGF-induced dorsal ruffle turnover and cell migration as demonstrated by both down-regulation of aPKCλ protein levels in cells by RNA interference and by studies in aPKCλ knock-out cells. Moreover, phosphorylation of Ric-8A modulates its subcellular localization. Hence, aPKCλ is critical for PDGF-induced actin cytoskeletal reorganization and cell migration.