The Potential Functional Roles of NME1 Histidine Kinase Activity in Neuroblastoma Pathogenesis

Hsa_circ_ROBO1 competes with miR-324-3p and upregulates NME1 to promote tumor metastasis in nasopharyngeal carcinoma

BACKGROUND

This work aims to explore circ_ROBO1's function in nasopharyngeal carcinoma (NPC).

METHODS

circ_ROBO1 expression in NPC tissues and cell lines was measured. The regulation of circ_ROBO1 and/or miR-324-3p on the proliferation, migration, invasion, and apoptosis of NPC cells was investigated by functional experiments. The interplay between circ_ROBO1, miR-324-3p, and NME1 was explored. Tumor growth and metastasis were studied in mice.

RESULTS

circ_ROBO1 was overexpressed in NPC. Knockdown of circ_ROBO1 repressed proliferation, migration, and invasion and induced apoptosis of NPC cells. Loss of circ_ROBO1 reduced tumor growth and metastasis in mice. circ_ROBO1 competed with miR-324-3p to upregulate NME1. Lowering miR-324-3p expression impaired the effect of knockdown of circ_ROBO1on NPC cells.

CONCLUSION

Overexpressed circ_ROBO1 promotes NPC development by modifying the miR-324-3p/NME1 axis.

Histidine Phosphorylation: Protein Kinases and Phosphatases

Phosphohistidine (pHis) is a reversible protein post-translational modification (PTM) that is currently poorly understood. The P-N bond in pHis is heat and acid-sensitive, making it more challenging to study than the canonical phosphoamino acids pSer, pThr, and pTyr. As advancements in the development of tools to study pHis have been made, the roles of pHis in cells are slowly being revealed. To date, a handful of enzymes responsible for controlling this modification have been identified, including the histidine kinases NME1 and NME2, as well as the phosphohistidine phosphatases PHPT1, LHPP, and PGAM5. These tools have also identified the substrates of these enzymes, granting new insights into previously unknown regulatory mechanisms. Here, we discuss the cellular function of pHis and how it is regulated on known pHis-containing proteins, as well as cellular mechanisms that regulate the activity of the pHis kinases and phosphatases themselves. We further discuss the role of the pHis kinases and phosphatases as potential tumor promoters or suppressors. Finally, we give an overview of various tools and methods currently used to study pHis biology. Given their breadth of functions, unraveling the role of pHis in mammalian systems promises radical new insights into existing and unexplored areas of cell biology.

Prediction and assessment of deleterious and disease causing nonsynonymous single nucleotide polymorphisms (nsSNPs) in human FOXP4 gene: An in - silico study

In humans, FOXP gene family is involved in embryonic development and cancer progression. The FOXP4 (Forkhead box protein P4) gene belongs to this FOXP gene family. FOXP4 gene plays a crucial role in oncogenesis. Single nucleotide polymorphisms are biological markers and common determinants of human diseases. Mutations can largely affect the function of the corresponding protein. Therefore, the molecular mechanism of nsSNPs in the FOXP4 gene needs to be elucidated. Initially, the SNPs of the FOXP4 gene were extracted from the dbSNP database and a total of 23124 SNPs was found, where 555 nonsynonymous, 20525 intronic, 1114 noncoding transcript, 334 synonymous were obtained and the rest were unspecified. Then, a series of bioinformatics tools (SIFT, PolyPhen2, SNAP2, PhD SNP, PANTHER, I-Mutant2.0, MUpro, GOR IV, ConSurf, NetSurfP 2.0, HOPE, DynaMut2, GeneMANIA, STRING and Schrodinger) were used to explore the effect of nsSNPs on FOXP4 protein function and structural stability. First, 555 nsSNPs were analyzed using SIFT, of which 57 were found as deleterious. Following, PolyPhen2, SNAP2, PhD SNP and PANTHER analyses, 10 nsSNPs (rs372762294, rs141899153, rs142575732, rs376938850, rs367607523, rs112517943, rs140387832, rs373949416, rs373949416 and rs376160648) were common and observed as deleterious, damaging and diseases associated. Following that, using I-Mutant2.0 and MUpro servers, 7 nsSNPs were found to be the most unstable. GOR IV predicted that these seven nsSNPs affect protein structure by altering the protein contents of alpha helixes, extended strands, and random coils. Following DynaMut2, 5 nsSNPs showed a decrease in the ΔΔG value compared with the wild-type and were found to be responsible for destabilizing the corresponding protein. GeneMANIA and STRING network revealed interaction of FOXP4 with other genes. Finally, molecular dynamics simulation analysis revealed consistent fluctuation in RMSD and RMSF values, Rg and hydrogen bonds in the mutant proteins compared with WT, which might alter the functional and structural stability of the corresponding protein. As a result, the aforementioned integrated comprehensive bioinformatic analyses provide insight into how various nsSNPs of the FOXP4 gene change the structural and functional properties of the corresponding protein, potentially proceeding with the pathophysiology of human diseases.

A human neural crest model reveals the developmental impact of neuroblastoma-associated chromosomal aberrations

Early childhood tumours arise from transformed embryonic cells, which often carry large copy number alterations (CNA). However, it remains unclear how CNAs contribute to embryonic tumourigenesis due to a lack of suitable models. Here we employ female human embryonic stem cell (hESC) differentiation and single-cell transcriptome and epigenome analysis to assess the effects of chromosome 17q/1q gains, which are prevalent in the embryonal tumour neuroblastoma (NB). We show that CNAs impair the specification of trunk neural crest (NC) cells and their sympathoadrenal derivatives, the putative cells-of-origin of NB. This effect is exacerbated upon overexpression of MYCN, whose amplification co-occurs with CNAs in NB. Moreover, CNAs potentiate the pro-tumourigenic effects of MYCN and mutant NC cells resemble NB cells in tumours. These changes correlate with a stepwise aberration of developmental transcription factor networks. Together, our results sketch a mechanistic framework for the CNA-driven initiation of embryonal tumours.

LHPP expression in triple-negative breast cancer promotes tumor growth and metastasis by modulating the tumor microenvironment

Triple-negative breast cancer (TNBC) is a highly aggressive and metastatic form of breast cancer that lacks an effective targeted therapy. To identify new therapeutic targets, we investigated the phosphohistidine phosphatase, LHPP, which has been implicated in the development of several types of cancer. However, the full significance of LHPP in cancer progression remains unclear due to our limited understanding of its molecular mechanism. We found that levels of the LHPP phosphohistidine phosphatase were significantly increased in human breast cancer patients compared to normal adjacent tissues, with the highest levels in the TNBC subtype. When LHPP was knocked out in the MDA-MB-231 human TNBC cell line, cell proliferation, wound healing capacity, and invasion were significantly reduced. However, LHPP knockout in TNBC cells did not affect the phosphohistidine protein levels. Interestingly, LHPP knockout in MDA-MB-231 cells delayed tumor growth and reduced metastasis when orthotopically transplanted into mouse mammary glands. To investigate LHPP's role in breast cancer progression, we used next-generation sequencing and proximity-labeling proteomics, and found that LHPP regulates gene expression in chemokine-mediated signaling and actin cytoskeleton organization. Depletion of LHPP reduced the presence of tumor-infiltrating macrophages in mouse xenografts. Our results uncover a new tumor promoter role for LHPP phosphohistidine phosphatase in TNBC and suggest that targeting LHPP phosphatase could be a potential therapeutic strategy for TNBC.

Revolutionizing pediatric neuroblastoma treatment: unraveling new molecular targets for precision interventions

Neuroblastoma (NB) is the most frequent solid tumor in pediatric cases, contributing to around 15% of childhood cancer-related deaths. The wide-ranging genetic, morphological, and clinical diversity within NB complicates the success of current treatment methods. Acquiring an in-depth understanding of genetic alterations implicated in the development of NB is essential for creating safer and more efficient therapies for this severe condition. Several molecular signatures are being studied as potential targets for developing new treatments for NB patients. In this article, we have examined the molecular factors and genetic irregularities, including those within insulin gene enhancer binding protein 1 (ISL1), dihydropyrimidinase-like 3 (DPYSL3), receptor tyrosine kinase-like orphan receptor 1 (ROR1) and murine double minute 2-tumor protein 53 (MDM2-P53) that play an essential role in the development of NB. A thorough summary of the molecular targeted treatments currently being studied in pre-clinical and clinical trials has been described. Recent studies of immunotherapeutic agents used in NB are also studied in this article. Moreover, we explore potential future directions to discover new targets and treatments to enhance existing therapies and ultimately improve treatment outcomes and survival rates for NB patients.

17q Gain in Neuroblastoma: A Review of Clinical and Biological Implications

Neuroblastoma (NB) is the most frequent extracranial solid childhood tumor. Despite advances in the understanding and treatment of this disease, the prognosis in cases of high-risk NB is still poor. 17q gain has been shown to be the most frequent genomic alteration in NB. However, the significance of this remains unclear because of its high frequency and association with other genetic modifications, particularly segmental chromosomal aberrations, 1p and 11q deletions, and MYCN amplification, all of which are also associated with a poor clinical prognosis. This work reviewed the evidence on the clinical and biological significance of 17q gain. It strongly supports the significance of 17q gain in the development of NB and its importance as a clinically relevant marker. However, it is crucial to distinguish between whole and partial chromosome 17q gains. The most important breakpoints appear to be at 17q12 and 17q21. The former distinguishes between whole and partial chromosome 17q gain; the latter is a site of IGF2BP1 and NME1 genes that appear to be the main oncogenes responsible for the functional effects of 17q gain.

NME6 as a potential biomarker and therapeutic target involved in immune infiltration for lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD), a prevalent form of lung cancer, is characterized by its high global mortality rate. Previous studies have demonstrated the significance of Nucleoside diphosphate kinase (NME) in various cancers; however, the specific role of NME6 in LUAD remains inadequately understood.

OBJECTIVE

This research aims to enhance our understanding of LUAD by investigating the expression level, epigenetic mechanism, signaling activities, and immune infiltrating characteristic immune cells of NME6 in patients.

METHODS

The NME6 expression was explored between LUAD and normal tissue samples using GEPIA, UALCAN and HPA databases. The survival analysis was performed by Kaplan-Meier plotter. The Shiny Methylation Analysis Resource Tool was employed to examine the methylation characteristics of NME6. The Tumor Immune Single-cell Hub (TISCH) and CIBERSORT algorithm were utilized to analyze immune infiltrating characteristic immune cells between NME6 high- and low-expression group in LUAD.

RESULTS

According to GEPIA, UALCAN, and HPA databases, NME6 is highly expressed in LUAD compared to normal tissues. At the same time, elevated levels of NME6 were found to be significantly correlated with inferior overall survival outcomes in LUAD patients. Subsequently, the top 10 genes interacted with NME6 were mainly involved in seven pathways, such as p53 signaling pathway, glutathione metabolism, thiamine metabolism, metabolic pathways, and drug metabolism. Notably, NME6 methylation in LUAD samples was lower than in normal samples. The methylation of cg04625862 has a significant impact on the regulation of NME6 expression in LUAD. Furthermore, high NME6 expression in LUAD was associated with tumor stages and relative abundance of tumor infiltrating immune cells, such as Macrophage M2, activated mast cell, and neutrophil. Moreover, NME6 regulated the expression of m6A modification of genes related to LUAD, including METTL3, WTAP, RBM15B, METTL14, RBMX, VIRMA, YTHDC1, RBM15, ZC3H13, YTHDF1, YTHDC2, IGF2BP2, YTHDF3, HNRNPA2B1, YTHDF2, HNRNPC, FTO, and ALKBH5.

CONCLUSION

The analysis showed that NME6 is a crucial prognostic factor for LUAD patients. NME6 regulates genes related to m6A modification and immune cells infiltration. Furthermore, NME6 could sever as a potential therapeutic target for LUAD.

IGF2BP1 induces neuroblastoma via a druggable feedforward loop with MYCN promoting 17q oncogene expression

BACKGROUND

Neuroblastoma is the most common solid tumor in infants accounting for approximately 15% of all cancer-related deaths. Over 50% of high-risk neuroblastoma relapse, emphasizing the need of novel drug targets and therapeutic strategies. In neuroblastoma, chromosomal gains at chromosome 17q, including IGF2BP1, and MYCN amplification at chromosome 2p are associated with adverse outcome. Recent, pre-clinical evidence indicates the feasibility of direct and indirect targeting of IGF2BP1 and MYCN in cancer treatment.

METHODS

Candidate oncogenes on 17q were identified by profiling the transcriptomic/genomic landscape of 100 human neuroblastoma samples and public gene essentiality data. Molecular mechanisms and gene expression profiles underlying the oncogenic and therapeutic target potential of the 17q oncogene IGF2BP1 and its cross-talk with MYCN were characterized and validated in human neuroblastoma cells, xenografts and PDX as well as novel IGF2BP1/MYCN transgene mouse models.

RESULTS

We reveal a novel, druggable feedforward loop of IGF2BP1 (17q) and MYCN (2p) in high-risk neuroblastoma. This promotes 2p/17q chromosomal gains and unleashes an oncogene storm resulting in fostered expression of 17q oncogenes like BIRC5 (survivin). Conditional, sympatho-adrenal transgene expression of IGF2BP1 induces neuroblastoma at a 100% incidence. IGF2BP1-driven malignancies are reminiscent to human high-risk neuroblastoma, including 2p/17q-syntenic chromosomal gains and upregulation of Mycn, Birc5, as well as key neuroblastoma circuit factors like Phox2b. Co-expression of IGF2BP1/MYCN reduces disease latency and survival probability by fostering oncogene expression. Combined inhibition of IGF2BP1 by BTYNB, MYCN by BRD inhibitors or BIRC5 by YM-155 is beneficial in vitro and, for BTYNB, also.

CONCLUSION

We reveal a novel, druggable neuroblastoma oncogene circuit settling on strong, transcriptional/post-transcriptional synergy of MYCN and IGF2BP1. MYCN/IGF2BP1 feedforward regulation promotes an oncogene storm harboring high therapeutic potential for combined, targeted inhibition of IGF2BP1, MYCN expression and MYCN/IGF2BP1-effectors like BIRC5.

Signature literature review reveals AHCY, DPYSL3, and NME1 as the most recurrent prognostic genes for neuroblastoma

Neuroblastoma is a childhood neurological tumor which affects hundreds of thousands of children worldwide, and information about its prognosis can be pivotal for patients, their families, and clinicians. One of the main goals in the related bioinformatics analyses is to provide stable genetic signatures able to include genes whose expression levels can be effective to predict the prognosis of the patients. In this study, we collected the prognostic signatures for neuroblastoma published in the biomedical literature, and noticed that the most frequent genes present among them were three: AHCY, DPYLS3, and NME1. We therefore investigated the prognostic power of these three genes by performing a survival analysis and a binary classification on multiple gene expression datasets of different groups of patients diagnosed with neuroblastoma. Finally, we discussed the main studies in the literature associating these three genes with neuroblastoma. Our results, in each of these three steps of validation, confirm the prognostic capability of AHCY, DPYLS3, and NME1, and highlight their key role in neuroblastoma prognosis. Our results can have an impact on neuroblastoma genetics research: biologists and medical researchers can pay more attention to the regulation and expression of these three genes in patients having neuroblastoma, and therefore can develop better cures and treatments which can save patients' lives.

Comparison among Neuroblastoma Stages Suggests the Involvement of Mitochondria in Tumor Progression

Neuroblastoma (NB) is the most common extracranial tumor of early childhood and accounts for 15% of all pediatric cancer mortalities. However, the precise pathways and genes underlying its progression are unknown. Therefore, we performed a differential gene expression analysis of neuroblastoma stage 1 and stage 4 + 4S to discover biological processes associated with NB progression. From this preliminary analysis, we found that NB samples (stage 4 + 4S) are characterized by altered expression of some proteins involved in mitochondria function and mitochondria-ER contact sites (MERCS). Although further analyses remain necessary, this review may provide new hints to better understand NB molecular etiopathogenesis, by suggesting that MERCS alterations could be involved in the progression of NB.

Phosphohistidine signaling promotes FAK-RB1 interaction and growth factor-independent proliferation of esophageal squamous cell carcinoma

Current clinical therapies targeting receptor tyrosine kinases including focal adhesion kinase (FAK) have had limited or no effect on esophageal squamous cell carcinoma (ESCC). Unlike esophageal adenocarcinomas, ESCC acquire glucose in excess of their anabolic need. We recently reported that glucose-induced growth factor-independent proliferation requires the phosphorylation of FAK^His58. Here, we confirm His58 phosphorylation in FAK immunoprecipitates of glucose-stimulated, serum-starved ESCC cells using antibodies specific for 3-phosphohistidine and mass spectrometry. We also confirm a role for the histidine kinase, NME1, in glucose-induced FAK^poHis58 and ESCC cell proliferation, correlating with increased levels of NME1 in ESCC tumors versus normal esophageal tissues. Unbiased screening identified glucose-induced retinoblastoma transcriptional corepressor 1 (RB1) binding to FAK, mediated through a "LxCxE" RB1-binding motif in FAK's FERM domain. Importantly, in the absence of growth factors, glucose increased FAK scaffolding of RB1 in the cytoplasm, correlating with increased ESCC G1→S phase transition. Our data strongly suggest that this glucose-mediated mitogenic pathway is novel and represents a unique targetable opportunity in ESCC.

Assessment of the Anticancer Potentials of the Free and Metal-Organic Framework (UiO-66) - Delivered Phycocyanobilin

Phycocyanin (C-PC) is a constitutive chromoprotein of Arthrospira platensis, which exhibits promising efficacy against different types of cancer. In this study, we cleaved C-PC's chromophore phycocyanobilin (PCB) and demonstrated its ability as an anti-cancer drug for Colorectal cancer (CRC). PCB displayed an anti-cancer effect for CRC (HT-29) cells with IC50 of 108 µg/ml. Assessing the transcripts levels of some biomarkers revealed that the PCB caused an upregulation in the anti-metastatic gene NME1 level and downregulation of the COX-2 level. The flow cytometric results showed the effect of PCB on the arrest of the cell cycle's G1 phase. In addition, we successfully synthesized the UiO-66 (Zr-MOF). We incorporated the PCB into UiO-66 nanoparticles with a loading percentage of 46 %. Assessment of the cytotoxic effects of UiO-66@PCB showed a 2-fold improvement in the IC50 compared to the free PCB. In conclusion, we have shown that PCB displayed a promising potential as an anti-cancer agent. Yet, it is considered a safe and natural substance that can help to mitigate cancer spread and symptoms. In the meantime, UiO-66 can be used as a safe nano-delivery tool for PCB.

Not your Mother's MAPKs: Apicomplexan MAPK function in daughter cell budding

Reversible phosphorylation by protein kinases is one of the core mechanisms by which biological signals are propagated and processed. Mitogen-activated protein kinases, or MAPKs, are conserved throughout eukaryotes where they regulate cell cycle, development, and stress response. Here, we review advances in our understanding of the function and biochemistry of MAPK signaling in apicomplexan parasites. As expected for well-conserved signaling modules, MAPKs have been found to have multiple essential roles regulating both Toxoplasma tachyzoite replication and sexual differentiation in Plasmodium. However, apicomplexan MAPK signaling is notable for the lack of the canonical kinase cascade that normally regulates the networks, and therefore must be regulated by a distinct mechanism. We highlight what few regulatory relationships have been established to date, and discuss the challenges to the field in elucidating the complete MAPK signaling networks in these parasites.

A journey from phosphotyrosine to phosphohistidine and beyond

Protein phosphorylation is a reversible post-translational modification. Nine of the 20 natural amino acids in proteins can be phosphorylated, but most of what we know about the roles of protein phosphorylation has come from studies of serine, threonine, and tyrosine phosphorylation. Much less is understood about the phosphorylation of histidine, lysine, arginine, cysteine, aspartate, and glutamate, so-called non-canonical phosphorylations. Phosphohistidine (pHis) was discovered 60 years ago as a mitochondrial enzyme intermediate; since then, evidence for the existence of histidine kinases and phosphohistidine phosphatases has emerged, together with examples where protein function is regulated by reversible histidine phosphorylation. pHis is chemically unstable and has thus been challenging to study. However, the recent development of tools for studying pHis has accelerated our understanding of the multifaceted functions of histidine phosphorylation, revealing a large number of proteins that are phosphorylated on histidine and implicating pHis in a wide range of cellular processes.

The Complex Functions of the NME Family-A Matter of Location and Molecular Activity

The family of NME proteins represents a quite complex group of multifunctional enzymes [...].

Targeting Oncogenic Transcriptional Networks in Neuroblastoma: From N-Myc to Epigenetic Drugs

Neuroblastoma (NB) is one of the most frequently occurring neurogenic extracranial solid cancers in childhood and infancy. Over the years, many pieces of evidence suggested that NB development is controlled by gene expression dysregulation. These unleashed programs that outline NB cancer cells make them highly dependent on specific tuning of gene expression, which can act co-operatively to define the differentiation state, cell identity, and specialized functions. The peculiar regulation is mainly caused by genetic and epigenetic alterations, resulting in the dependency on a small set of key master transcriptional regulators as the convergence point of multiple signalling pathways. In this review, we provide a comprehensive blueprint of transcriptional regulation bearing NB initiation and progression, unveiling the complexity of novel oncogenic and tumour suppressive regulatory networks of this pathology. Furthermore, we underline the significance of multi-target therapies against these hallmarks, showing how novel approaches, together with chemotherapy, surgery, or radiotherapy, can have substantial antineoplastic effects, disrupting a wide variety of tumorigenic pathways through combinations of different treatments.

Immune classification and identification of prognostic genes for uveal melanoma based on six immune cell signatures

Cutaneous melanoma could be treated by immunotherapy, which only has limited efficacy on uveal melanoma (UM). UM immunotyping for predicting immunotherapeutic responses and guiding immunotherapy should be better understood. This study identified molecular subtypes and key genetic markers associated with immunotherapy through immunosignature analysis. We screened a 6-immune cell signature simultaneously correlated with UM prognosis. Three immune subtypes (IS) were determined based on the 6-immune cell signature. Overall survival (OS) of IS3 was the longest. Significant differences of linear discriminant analysis (LDA) score were detected among the three IS types. IS3 with the highest LDA score showed a low immunosuppression. IS1 with the lowest LDA score was more immunosuppressive. LDA score was significantly negatively correlated with most immune checkpoint-related genes, and could reflect UM patients’ response to anti-PD1 immunotherapy. Weighted correlation network analysis (WGCNA) identified that salmon, purple, yellow modules were related to IS and screened 6 prognostic genes. Patients with high-expressed NME1 and TMEM255A developed poor prognosis, while those with high-expressed BEX5 and ROPN1 had better prognosis. There was no notable difference in OS between patients with high-expressed LRRN1 and ST13 and those with low-expressed LRRN1 and ST13. NME1, TMEM255A, Bex5 and ROPN1 showed potential prognostic significance in UM.

The Potential Role of Human NME1 in Neuronal Differentiation of Porcine Mesenchymal Stem Cells: Application of NB-hNME1 as a Human NME1 Suppressor

This study aimed to investigate the effects of the human macrophage (MP) secretome in cellular xenograft rejection. The role of human nucleoside diphosphate kinase A (hNME1), from the secretome of MPs involved in the neuronal differentiation of miniature pig adipose tissue-derived mesenchymal stem cells (mp AD-MSCs), was evaluated by proteomic analysis. Herein, we first demonstrate that hNME1 strongly binds to porcine ST8 alpha-N-acetyl-neuraminide alpha-2,8-sialyltransferase 1 (pST8SIA1), which is a ganglioside GD3 synthase. When hNME1 binds with pST8SIA1, it induces degradation of pST8SIA1 in mp AD-MSCs, thereby inhibiting the expression of ganglioside GD3 followed by decreased neuronal differentiation of mp AD-MSCs. Therefore, we produced nanobodies (NBs) named NB-hNME1 that bind to hNME1 specifically, and the inhibitory effect of NB-hNME1 was evaluated for blocking the binding between hNME1 and pST8SIA1. Consequently, NB-hNME1 effectively blocked the binding of hNME1 to pST8SIA1, thereby recovering the expression of ganglioside GD3 and neuronal differentiation of mp AD-MSCs. Our findings suggest that mp AD-MSCs could be a potential candidate for use as an additive, such as an immunosuppressant, in stem cell transplantation.

The first central precocious puberty proteomic profiles revealed multiple metabolic networks and novel key disease-associated proteins

Though central precocious puberty (CPP) as a disease that seriously affects the development of a child is increasing year by year, treatment options remain limited and is the same as the 1980s’ method. These are mainly due to the complex pathogenesis of central precocious puberty. Therefore, systems biology approach to identify and explore the multiple factors related to the pathogenesis of central precocious puberty is necessary. Our data established the first proteome profile of CPP revealed 163 down-regulated and 129 were up-regulated differentially expressed proteins. These altered proteins were primarily enriched in three metabolic process including energy metabolism, amino acid metabolism and nitrogenous base metabolism. The identified altered members of the metabolic signaling are valuable and potential novel therapeutic targets of central precocious puberty.

The many ways that nature has exploited the unusual structural and chemical properties of phosphohistidine for use in proteins

Histidine phosphorylation is an important and ubiquitous post-translational modification. Histidine undergoes phosphorylation on either of the nitrogens in its imidazole side chain, giving rise to 1- and 3- phosphohistidine (pHis) isomers, each having a phosphoramidate linkage that is labile at high temperatures and low pH, in contrast with stable phosphomonoester protein modifications. While all organisms routinely use pHis as an enzyme intermediate, prokaryotes, lower eukaryotes and plants also use it for signal transduction. However, research to uncover additional roles for pHis in higher eukaryotes is still at a nascent stage. Since the discovery of pHis in 1962, progress in this field has been relatively slow, in part due to a lack of the tools and techniques necessary to study this labile modification. However, in the past ten years the development of phosphoproteomic techniques to detect phosphohistidine (pHis), and methods to synthesize stable pHis analogues, which enabled the development of anti-phosphohistidine (pHis) antibodies, have accelerated our understanding. Recent studies that employed anti-pHis antibodies and other advanced techniques have contributed to a rapid expansion in our knowledge of histidine phosphorylation. In this review, we examine the varied roles of pHis-containing proteins from a chemical and structural perspective, and present an overview of recent developments in pHis proteomics and antibody development.

HisPhosSite: A comprehensive database of histidine phosphorylated proteins and sites

Histidine phosphorylation is critically important in a variety of cellular processes including signal transduction, cell cycle, proliferation, differentiation, and apoptosis. It is estimated to account for 6% of all phosphorylated amino acids. However, due to the acid lability of the PN bond, the study of pHis lags far behind that of pSer, pThr, and pTyr. Recently, the development and use of pHis-specific antibodies and methodologies have led to a resurgence in the study of histidine phosphorylation. Although a considerable number of pHis proteins and sites have been discovered, most of them have not been manually curated and integrated to any databases. There is a lack of a data repository for pHis, and such work is expected to help further systemic studies of pHis. Thus, we present a comprehensive resource database of histidine phosphorylation (HisPhosSite) by curating experimentally validated pHis proteins and sites and compiling putative pHis sites with ortholog search. HisPhosSite contains 776 verified pHis sites and 2702 verified pHis proteins in 38 eukaryotic and prokaryotic species and 15,378 putative pHis sites and 10,816 putative pHis proteins in 1366 species. HisPhosSite provides rich annotations of pHis sites and proteins and multiple search engines (including motif search and BLAST search) for users to locate pHis sites of interest. HisPhosSite is available at http://reprod.njmu.edu.cn/hisphossite. SIGNIFICANCE: Histidine phosphorylation is involved in a variety of cellular processes as well as cancers, and it has been proved to be more common than previously thought. The HisPhosSite database was developed to collect pHis data from published literatures with experimental evidences. Unification of the identified pHis proteins and sites will give researchers an informative resource for histidine phosphorylation. HisPhosSite has a user-friendly interface with multiple search engines for users to locate pHis sites of interest. In addition, the database provides rich structural and functional annotations. HisPhosSite will help future studies and elucidation of the functions of histidine phosphorylation.

NME/NM23/NDPK and Histidine Phosphorylation

The NME (Non-metastatic) family members, also known as NDPKs (nucleoside diphosphate kinases), were originally identified and studied for their nucleoside diphosphate kinase activities. This family of kinases is extremely well conserved through evolution, being found in prokaryotes and eukaryotes, but also diverges enough to create a range of complexity, with homologous members having distinct functions in cells. In addition to nucleoside diphosphate kinase activity, some family members are reported to possess protein-histidine kinase activity, which, because of the lability of phosphohistidine, has been difficult to study due to the experimental challenges and lack of molecular tools. However, over the past few years, new methods to investigate this unstable modification and histidine kinase activity have been reported and scientific interest in this area is growing rapidly. This review presents a global overview of our current knowledge of the NME family and histidine phosphorylation, highlighting the underappreciated protein-histidine kinase activity of NME family members, specifically in human cells. In parallel, information about the structural and functional aspects of the NME family, and the knowns and unknowns of histidine kinase involvement in cell signaling are summarized.