Correction: The Rho/ROCK pathway for lysophosphatidic acid-induced proteolytic enzyme expression and ovarian cancer cell invasion.

The original version of this article contained an error in the published figures Fig 2 and Fig 3f, where the information was inadvertently duplicated. This error does not alter the conclusions of the paper. The corrected figures are published in this correction notice. The authors sincerely apologize for this error.

Correction: RCP induces Slug expression and cancer cell invasion by stabilizing ß1 integrin.

Following the publication of this article the authors noted that images were inadvertently duplicated in Fig. 1b. The corrected Fig. 1 can be found in the associated Correction. The conclusions of this paper are not affected. The authors sincerely apologize for this error. This error has not been corrected in the HTML or PDF of the original Article.

Core-shell nanoparticle arrays double the strength of steel.

Manipulating structure, defects and composition of a material at the atomic scale for enhancing its physical or mechanical properties is referred to as nanostructuring. Here, by combining advanced microscopy techniques, we unveil how formation of highly regular nano-arrays of nanoparticles doubles the strength of an Fe-based alloy, doped with Ti, Mo, and V, from 500 MPa to 1 GPa, upon prolonged heat treatment. The nanoparticles form at moving heterophase interfaces during cooling from the high-temperature face-centered cubic austenite to the body-centered cubic ferrite phase. We observe MoC and TiC nanoparticles at early precipitation stages as well as core-shell nanoparticles with a Ti-C rich core and a Mo-V rich shell at later precipitation stages. The core-shell structure hampers particle coarsening, enhancing the material's strength. Designing such highly organized metallic core-shell nanoparticle arrays provides a new pathway for developing a wide range of stable nano-architectured engineering metallic alloys with drastically enhanced properties.

RCP induces Slug expression and cancer cell invasion by stabilizing ß1 integrin.

Rab coupling protein (RCP)-induced tumor cell migration has been implicated in tumor pathophysiology and patient outcomes. In the present study, we demonstrate that RCP stabilizes ß1 integrin leading to increased ß1 integrin levels and activation of a signaling cascade culminating in Slug induction, epithelial-to-mesenchymal transition and increased invasion. Ectopic expression of RCP induced Slug expression. Silencing ß1 integrin efficiently inhibited RCP-induced Slug expression and subsequent cancer cell invasion. Conversely, ectopic expression of ß1 integrin was sufficient to induce Slug expression. Pharmacological inhibition of integrin linked kinase (ILK), EGFR and NF-κB, as well as transfection of a dominant-negative mutant of Ras (RasN17), significantly inhibited RCP-induced Slug expression and cancer cell invasion. Strikingly, ectopic expression of RCP was sufficient to enhance metastasis of ovarian cancer cells to the lung. Collectively, we demonstrate a mechanism by which RCP promotes cancer cell aggressiveness through sequential ß1 integrin stabilization, activation of an ILK/EGFR/Ras/NF-κB signaling cascade and subsequent Slug expression.

Long-term control of diabetes in immunosuppressed nonhuman primates (NHP) by the transplantation of adult porcine islets.

Pig islets are an alternative source for islet transplantation to treat type 1 diabetes (T1D), but reproducible curative potential in the pig-to-nonhuman primate (NHP) model has not been demonstrated. Here, we report that pig islet grafts survived and maintained normoglycemia for >6 months in four of five consecutive immunosuppressed NHPs. Pig islets were isolated from designated pathogen-free (DPF) miniature pigs and infused intraportally into streptozotocin-induced diabetic rhesus monkeys under pretreatment with cobra venom factor (CVF), anti-thymocyte globulin (ATG) induction and maintenance with anti-CD154 monoclonal antibody and low-dose sirolimus. Ex vivo expanded autologous regulatory T cells were adoptively transferred in three recipients. Blood glucose levels were promptly normalized in all five monkeys and normoglycemia (90-110 mg/dL) was maintained for >6 months in four cases, the longest currently up to 603 days. Intravenous glucose tolerance tests during the follow-up period showed excellent glucose disposal capacity and porcine C-peptide responses. Adoptive transfer of autologous regulatory T cells was likely to be associated with more stable and durable normoglycemia. Importantly, the recipients showed no serious adverse effects. Taken together, our results confirm the clinical feasibility of pig islet transplantation to treat T1D patients without the need for excessive immunosuppressive therapy.

The LIM-only transcription factor LMO2 determines tumorigenic and angiogenic traits in glioma stem cells.

Glioblastomas (GBMs) maintain their cellular heterogeneity with glioma stem cells (GSCs) producing a variety of tumor cell types. Here we interrogated the oncogenic roles of Lim domain only 2 (LMO2) in GBM and GSCs in mice and human. High expression of LMO2 was found in human patient-derived GSCs compared with the differentiated progeny cells. LMO2 is required for GSC proliferation both in vitro and in vivo, as shRNA-mediated LMO2 silencing attenuated tumor growth derived from human GSCs. Further, LMO2 is sufficient to induce stem cell characteristics (stemness) in mouse premalignant astrocytes, as forced LMO2 expression facilitated in vitro and in vivo growth of astrocytes derived from Ink4a/Arf null mice and acquisition of GSC phenotypes. A subset of mouse and human GSCs converted into vascular endothelial-like tumor cells both in vitro and in vivo, which phenotype was attenuated by LMO2 silencing and promoted by LMO2 overexpression. Mechanistically, the action of LMO2 for induction of glioma stemness is mediated by transcriptional regulation of Jagged1 resulting in activation of the Notch pathway, whereas LMO2 directly occupies the promoter regions of the VE-cadherin gene for a gain of endothelial cellular phenotype. Subsequently, selective ablation of human GSC-derived VE-cadherin-expressing cells attenuated vascular formation in mouse intracranial tumors, thereby significantly prolonging mouse survival. Clinically, LMO2 expression was elevated in GBM tissues and inversely correlated with prognosis of GBM patients. Taken together, our findings describe novel dual roles of LMO2 to induce tumorigenesis and angiogenesis, and provide potential therapeutic targets in GBMs.

Co-transplantation of bone marrow-derived endothelial progenitor cells improves revascularization and organization in islet grafts.

Bone marrow-derived early endothelial progenitor cells (BM-EPCs) are a clinical tool for enhancing revascularization. However, the therapeutic efficacy of co-transplantation of BM-EPC with islets has not been investigated. In this study, marginal mass islets were co-transplanted with or without BM-EPCs under the kidney capsules of syngeneic streptozotocin-induced diabetic mice. Using green fluorescent protein transgenic (GFP-Tg) mice as BM-EPC and islet donors or recipients, the role of EPCs in revascularization was assessed for graft morphology, vascular density and fate of EPCs by immunohistochemistry. Islet-EPC co-transplantation improved the outcome of islet transplantation as measured by glucose tolerance, serum insulin level and diabetes reversal rate, compared with transplantation of islets alone. Between groups, the morphology of islet grafts showed significant differences in size and composition of grafted endocrine tissues. Significantly more vessel density derived from donors and recipients was detected with islet-EPC co-transplantation. Abundant GFP-Tg mice-derived BM-EPCs (GFP-EPCs) were observed in or around islet grafts and incorporated into CD31-positive capillaries. Remaining GFP-EPCs expressed VEGF. In conclusion, co-transplantation of islets with BM-EPCs could improve the outcome of marginal mass islet transplantation by promoting revascularization and preserving islet morphology.

The Rho/ROCK pathway for lysophosphatidic acid-induced proteolytic enzyme expression and ovarian cancer cell invasion.

Lysophosphatidic acid (LPA) is a biolipid that has diverse biological activities implicated in ovarian cancer initiation and progression. Previous studies have shown the critical role of the Rho/Rho-associated kinase (ROCK) pathway in LPA-induced ovarian cancer progression. However, detailed underlying mechanism by which the Rho/ROCK pathway induces ovarian cancer cell invasion is still incompletely understood. In the present study, we observed that the Rho/ROCK pathway is implicated in the production of proteolytic enzymes, leading to LPA-induced ovarian cancer cell invasion. LPA induced matrix metalloproteinase (MMP)-9 expression in CAOV-3 and PA-1 cells and urokinase-type plasminogen activator (uPA) expression in SKOV-3 cells. LPA-induced proteolytic enzyme expression was required for the invasion of ovarian cancer cells expressing corresponding enzymes. Pretreatment of cells with a pharmacological inhibitor of Rho/ROCK (Y-27632) or overexpression of a dominant-negative mutant of Rho (Rho N19) profoundly inhibited LPA-induced proteolytic enzyme expression as well as the invasive potential of ovarian cancer cells. In addition, transfection with dominant-negative Ras (Ras N17) significantly inhibited LPA-induced Rho activation as well as MMP-9 and uPA expression. Consistently, Y-27632 reduced LPA-induced nuclear factor (NF)-κB activation that is critical for proteolytic enzyme expression and cellular invasion. Collectively, we demonstrate a mechanism by which LPA promotes ovarian cancer progression through coordinate activation of a Ras/Rho/ROCK/NF-κB signaling pathway and the proteolytic enzyme secretion, providing novel biomarkers and promising therapeutic targets for ovarian cancer cell progression.

Acute necrotic stomatitis (noma) associated with methicillin-resistant Staphylococcus aureus infection in a newly acquired rhesus macaque (Macaca mulatta).

BACKGROUND: A newly acquired rhesus macaque was suffering from rapid destruction of the left cheek caused by necrotizing stomatitis. METHODS: To restore reconstructive surgery and intensive care with antibiotics, wound protection, wound healing agents, and debridement were applied. RESULTS: Staphylococcus aureus and Enterococcus faecalis were isolated from the culture of the lesion, and the antibiotic susceptibility test revealed methicillin-resistant Staphylococcus aureus infection. Vancomycin and ampicillin-sulbactam effectively treated the bacterial infections, and reconstructive surgery was performed once the infection was cleared. Topical application of recombinant human epidermal growth factor (rhEGF) was useful to treat exposed wound of the noma lesion. CONCLUSIONS: Simian noma associated with methicillin-resistant Staphylococcus aureus (MRSA) had not previously been reported in non-human primates. Although noma associated with MRSA is hard to cure because of its rapid and destructive progress, the aggressive therapy used in this study led to the successful resolution of an acute necrotic stomatitis lesion in a rhesus macaque.

Lysophosphatidic acid augments human hepatocellular carcinoma cell invasion through LPA1 receptor and MMP-9 expression.

Lysophosphatidic acid (LPA), produced extracellularly by autotaxin (ATX), has diverse biological activities implicated in tumor initiation and progression, including increasing cell survival, angiogenesis, invasion and metastasis. ATX, LPA and the matrix metalloproteinase (MMP)-9 have all been implicated in hepatocellular carcinoma (HCC) invasion and metastasis. We, thus sought to determine whether ATX with subsequent LPA production and action, including induction of MMP-9 could provide a unifying mechanism. ATX transcripts and LPA receptor type 1 (LPA1) protein are elevated in HCC compared with normal tissues. Silencing or pharmacological inhibition of LPA1 significantly attenuated LPA-induced MMP-9 expression and HCC cell invasion. Further, reducing MMP-9 activity or expression significantly inhibits LPA-induced HCC cell invasion, demonstrating that MMP-9 is downstream of LPA1. Inhibition of phosphoinositide-3 kinase (PI3K) signaling or dominant-negative mutants of protein kinase Cδ and p38 mitogen-activated protein kinase (MAPK) abrogated LPA-induced MMP-9 expression and subsequent invasion. We thus demonstrate a mechanistic cascade of ATX-producing LPA with LPA activating LPA1 and inducing MMP-9 through coordinate activation of the PI3K and the p38 MPAK signaling cascades, providing novel biomarkers and potential therapeutic targets for HCC.

Infection of porcine cells with human herpesviruses.

Porcine organs are valuable candidate materials for xenotransplantation to humans. Long-term maintenance of well functioning transplants is a prerequisite for success. Transplanted organs may be damaged by immune reactions or by infectious agents in hosts. Human herpesviruses (HHVs) establish life-long latency in humans after a primary infection. They can be reactivated with various stimuli, including immunosuppression. This study was performed to verify the infectivity of some HHVs toward porcine cells. PK-15 cells infected with HHV-1 and HHV-2 showed cytopathology from 1 day after infection. Immunofluorescent (IF) staining of HHV-1- and HHV-2-infected PK-15 cells with respective antibodies demonstrated the expression of the respective viral antigens. Permissiveness of PK-15 to HHV-1 and -2 was confirmed by an infection test on Vero cells. Islet cells infected with HHV-5 showed no gross morphologic changes during the experimental course. A limited portion of islet cells reacted only to anti-IE1 and anti-IE2, but not to anti-UL44 or anti-gB antibody by IF staining, whereas a small portion of endothelial cells reacted to anti-IEs and anti-UL44, but not to anti-gB antibody. HHV-1 and -2 can permissively infect porcine cells, but HHV-5 infects a small proportion of cells with limited viral protein expression. HHV-4 could not transform peripheral blood mononuclear cells from miniature pigs. Collectively, because some HHVs can infect and damage porcine cells or impair their functions, HHVs should be cautiously monitored and controlled in humans when porcine cells or organs are transplanted to human beings.

Implication of lipocalin-2 and visfatin levels in patients with coronary heart disease.

OBJECTIVES: Visfatin and lipocalin-2 are novel adipokines associated with insulin resistance (IR) and obesity-related metabolic disorders. We compared lipocalin-2 and visfatin concentrations between patients with coronary heart disease (CHD) and control subjects and evaluated their association with cardiovascular risk factors. METHODS: We examined serum visfatin, lipocalin-2 levels, and cardiovascular risk factors in 91 subjects (49 patients with angiographically confirmed CHD versus 42 age- and gender-matched control participants). RESULTS: Circulating lipocalin-2 levels were significantly higher in patients with CHD compared with the control subjects (82.6+/-38.7 ng/ml versus 43.8+/-27.8 ng/ml; P<0.001). However, visfatin levels were not significantly different between patients with CHD and control subjects. Serum lipocalin-2 levels were positively associated with weight (r=0.26; P=0.036), fasting insulin (r=0.36; P=0.003), and IR (r=0.33; P=0.007), whereas these levels showed a negative correlation with high-density lipoprotein (HDL) cholesterol (r=-0.30; P=0.016) after adjustment for gender and body mass index. However, visfatin levels were not associated with any variables of the metabolic syndrome. The multiple regression analysis showed that lipocalin-2 levels were independently associated with HDL cholesterol and IR (R2=0.199). Furthermore, the multiple logistic regression analysis showed that systolic blood pressure, IR, and lipocalin-2 levels were independently associated with CHD. CONCLUSIONS: Serum lipocalin-2 levels were significantly elevated in patients with CHD and were independently associated with CHD. The present findings suggest that the measurement of serum lipocalin-2 levels may be useful for assessing CHD risk.

The prevalence of and risk factors for erosive oesophagitis and non-erosive reflux disease: a nationwide multicentre prospective study in Korea.

BACKGROUND: Prospective nationwide multicentre studies that have evaluated endoscopic findings and reflux symptoms using a well-designed questionnaire are very rare. AIM: To compare the prevalence rates of and risk factors for erosive oesophagitis and non-erosive reflux disease (NERD) in the Korean population. METHODS: A gastroscopic examination was performed on 25 536 subjects who visited 40 Healthcare Centers for a health check-up. A gastro-oesophageal reflux questionnaire and multivariate analysis were used to determine the risk factors for erosive oesophagitis and NERD. RESULTS: 2019 (8%) and 996 subjects (4%) had erosive oesophagitis and non-erosive reflux disease, respectively; only 58% of subjects with erosive oesophagitis had reflux symptoms. Multivariate analysis showed that the risk factors for erosive oesophagitis and NERD differed, i.e. those of erosive oesophagitis were male, a Helicobacter pylori eradication history, alcohol, body mass index > or =25 and hiatal hernia. In contrast, the risk factors for NERD were female, age <40 and > or =60 vs. 40-59 years, body mass index <23 and a monthly income <$1000, glucose > or =126 mg/dL, smoking, a stooping posture at work and antibiotic usage. CONCLUSIONS: The prevalence rates of erosive oesophagitis and NERD were 8% and 4%, respectively, in Korean health check-up subjects. The risk factors for erosive oesophagitis and NERD were found to differ, which indicates that their underlying pathogeneses are distinct.

Inflammation, insulin resistance, and glucose intolerance in acute myocardial infarction patients without a previous diagnosis of diabetes mellitus.

We examined the prevalence of impaired glucose metabolism and its association with inflammation and insulin resistance (IR) in acute myocardial infarction (AMI) patients without a previous diagnosis of diabetes. This prospective study enrolled 52 AMI patients, and 75-g oral glucose tolerance testing was performed on 30 patients at discharge and again 3 months later. We also measured serum adiponectin, high sensitive C-reactive protein, and IL-6 on both occasions. Data were compared with those of 30 type 2 diabetic patients without a history of AMI. Forty percent and 36.7% of AMI patients had impaired glucose tolerance (IGT) at discharge and at 3 months, respectively. The corresponding proportions for newly diagnosed diabetes are 33.0% and 30.0%. At discharge, AMI patients with IGT or diabetes showed higher high sensitive C-reactive protein and IL-6 levels compared with AMI patients with normal glucose tolerance or control type 2 diabetic patients. Furthermore, AMI patients with IGT or diabetes exhibited higher IR and lower serum adiponectin levels than AMI patients with normal glucose tolerance at 3 months after discharge. Previously undiagnosed diabetes and IGT are common in Korean patients with AMI. These glycometabolic abnormalities are associated with inflammation, IR, and serum adiponectin levels.

Dexamethasone suppresses the expansion and transdifferentiation of transplanted porcine neonatal pancreas cell clusters (NPCCs) into beta-cells in normal nude mice.

OBJECTIVES: This study was performed to investigate the effect of dexamethasone on the expansion and transdifferentiation of transplanted neonatal pancreas cell clusters (NPCCs) in vivo. METHODS: Porcine NPCCs were generated from 1 to 3-day-old neonatal pigs. After transplantation (Tx) of 4000 islet equivalents (IEqs) of NPCCs beneath the renal subcapsular space of normoglycemic nude mice, dexamethasone (Dx, 1 mg/kg) or vehicles were injected daily. Intraperitoneal glucose tolerance testing (ip-GTT) was performed at 4 weeks (n = 4) and 10 weeks (n = 7) after Tx. After harvesting the grafts, total graft and beta-cell graft mass were determined by morphometric analysis. RESULTS: Although the mean value of AUCg was elevated in the Dx-treated group at 10 weeks after Tx, the glucose levels of all the animals by ip-GTT were within the normal range. At 10 weeks after Tx, the relative volume, absolute mass of beta-cells in the graft, and total graft mass were significantly lower in the Dx-treated group (relative volume of beta-cells: 22.0% versus 35.3%, P < 0.05; beta-cells mass: 1.0 +/- 1.2 mg versus 2.2 +/- 5.6 mg, P < 0.05, total graft mass: 4.4 +/- 5.4 mg versus 6.3 +/- 1.3 mg, P < 0.05, Dx-treated versus control), but there was no difference at 4 weeks. Morphologically prominent cystic structures were observed in the Dx group at 10 weeks. CONCLUSION: Our results suggest that dexamethasone suppresses the expansion and transdifferentiation of transplanted porcine NPCCs into beta-cells in normal nude mice.

Expression of the intermediate filament vimentin in proliferating duct cells as a marker of pancreatic precursor cells.

OBJECTIVES: The expression of the intermediate filament (IF) vimentin, usually considered a marker of mesenchymal cells, has been observed in the epithelial cells during embryogenesis, carcinogenesis, and dedifferentiation, suggesting that it might be useful as a marker of proliferating precursor cells in the pancreas. METHODS: Rat pancreata at E18 and at different time points after partial pancreatectomy (Px) and human and neonatal pig pancreatic tissue sections and monolayer cultured pancreatic duct cells were observed. All tissues were simultaneously immunostained with pancytokeratin and vimentin antibodies. In costained duct cells, PDX-1 or PCNA expression was also analyzed using confocal microscope images. RESULTS: In the rat embryonic pancreas at E18, all epithelial cells that formed ductlike structures expressed both cytokeratin and vimentin IF, whereas no duct cells costained for IF in the adult rat or neonatal pig pancreas. Such costaining reappeared in the following order: common pancreatic duct, main ducts, foci of regeneration and then disappeared completely at 30 days after Px. In humans, costaining was found in only 1 diabetic patient's pancreatic section, which was accompanied by massive duct cell proliferation. In monolayer culture, most of the duct cells of human and neonatal pigs coexpressed both IF proteins. Only a few costained duct cells also expressed PDX-1, and most of those cells were also stained with PCNA in rat embryonic pancreas and regenerating foci after partial Px. CONCLUSIONS: Vimentin IF expression might be a useful marker for pancreatic precursor cells and could be used to investigate the concept of the dedifferentiation of fully matured duct cells during the process of the beta-cell neogenesis.

Coronary flow reserve is reflective of myocardial perfusion status in acute anterior myocardial infarction.

Our objective was to determine whether coronary vasodilatory reserve (CVR) correlates with the perfusion state of infarct zone in early recovery phase of acute anterior myocardial infarction (AMI). We studied 14 patients (11 males; mean age, 46 years) who had AMI and 6 control subjects who had chest pain but normal coronary angiograms. All patients underwent successful percutaneous revascularization of left anterior descending (LAD) coronary artery. Coronary flow velocity was measured using intracoronary (IC) Doppler at baseline and following IC injection of 18 microg of adenosine. Myocardial perfusion was evaluated by myocardial contrast echocardiography (MCE). CVR was higher in patients without a perfusion defect on MCE than in those with (2.48 +/- 0.21 vs. 1.66 +/- 0.13, P = 0.001). Subjects with a perfusion defect had a lower CVR than controls (1.66 +/- 0.13 vs.2.40 +/- 0.18, P < 0.05). CVR was > 2.0 in all subjects without a perfusion defect. There was a strong correlation between the magnitude of myocardial opacification in the LAD territory and CVR (r = 0.80, P < 0.01). Increase in peak diastolic flow velocity after adenosine infusion, but not systolic flow velocity, correlated with myocardial opacification index (r = 0.63, P = 0.016). CVR of infarct-related artery correlated closely with the perfusion status of the myocardium in infarct zone and those with a CVR > 2.0 had normal myocardial perfusion. These data suggest that CVR may be used to determine the perfusion state of the myocardium in the infarct zone, which is a known predictor of myocardial viability. Cathet. Cardiovasc. Intervent. 51:281-286, 2000.

Cross-chimeric analysis of selectivity of secretin and VPAC(1) receptor activation.

Agonist action at receptors is highly specific, affected by the structure of both ligand and receptor. Chimeric constructs of structurally related receptors and/or ligands that have biological differences provide an opportunity to correlate a specific structural domain with function. In this work, we have used a cross-chimeric approach to explore the structural basis for rat secretin and vasoactive intestinal polypeptide action at their closely related secretin and VPAC(1) receptors, belonging to class II of the G protein-coupled receptor superfamily. Multiple domains of both ligands and receptors contributed toward their selectivity, with differing combinations of such domains able to support high-potency interactions. The amino-terminal 15 residues of secretin were most critical for potent stimulation of secretin receptors, whereas either the amino- or carboxyl-terminal halves of vasoactive intestinal polypeptide, when complemented by Lys(15), provided potent stimulation of the VPAC(1) receptor. The amino terminus of the VPAC(1) receptor was most critical for potent response to vasoactive intestinal polypeptide, whereas the amino terminus of the secretin receptor was important, but not adequate, requiring the complementation of an extracellular loop domain for potent response to secretin. Differences in the distribution of these determinants within these receptors provided an opportunity to produce a more "universal" receptor that contained the first extracellular loop of the secretin receptor and the remainder of the VPAC(1) receptor. This cross-chimeric approach should be applied to other members of this receptor family to test the emerging themes and to expand these insights as broadly as possible.

Structural basis for the feedback regulation of Escherichia coli pantothenate kinase by coenzyme A.

Pantothenate kinase (PanK) is a key regulatory enzyme in the coenzyme A (CoA) biosynthetic pathway and catalyzes the phosphorylation of pantothenic acid to form phosphopantothenate. CoA is a feedback inhibitor of PanK activity by competitive binding to the ATP site. The structures of the Escherichia coli enzyme, in complex with a nonhydrolyzable analogue of ATP, 5'-adenylimido-diphosphate (AMPPNP), or with CoA, were determined at 2.6 and 2.5 A, respectively. Both structures show that two dimers occupy an asymmetric unit; each subunit has a alpha/beta mononucleotide-binding fold with an extensive antiparallel coiled coil formed by two long helices along the dimerization interface. The two ligands, AMPPNP and CoA, associate with PanK in very different ways, but their phosphate binding sites overlap, explaining the kinetic competition between CoA and ATP. Residues Asp(127), His(177), and Arg(243) are proposed to be involved in catalysis, based on modeling of the pentacoordinate transition state. The more potent inhibition by CoA, compared with the CoA thioesters, is explained by a tight interaction of the CoA thiol group with the side chains of aromatic residues, which is predicted to discriminate against the CoA thioesters. The PanK structure provides the framework for a more detailed understanding of the mechanism of catalysis and feedback regulation of PanK.