Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Macrophage stimulating protein (MSP) is a chemotactic factor for murine peritoneal macrophages. The receptor for human MSP was recently identified as the ron gene product, a transmembrane protein tyrosine kinase cloned from a human keratinocyte cDNA library. Here we report that MSP induced proliferation of murine primary keratinocytes and established keratinocyte cell lines in a concentration-dependent manner. The growth efficacy of MSP was comparable to that of epidermal growth factor and keratinocyte growth factor. In three of four cell lines tested in a chemotaxis chamber, MSP also stimulated migration of keratinocytes on a collagen type IV substratum. The action of MSP was mediated by specific binding of MSP to the STK gene product, a murine homologue of the RON MSP receptor. Binding of MSP to keratinocyte STK induced phosphorylation of the 150 kDa STK beta chain. Herbimycin A, a protein tyrosine kinase inhibitor, blocked MSP-mediated phosphorylation of the STK receptor as well as proliferation of keratinocytes, suggesting the importance of tyrosine kinase activity for transduction of the message delivered by MSP. Previously, the only known target cell for MSP was the resident peritoneal macrophage. These studies establish the keratinocyte as a new target cell for MSP. The action of MSP on keratinocytes may have implications for tissue repair, wound healing, and tumor growth.
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PMID:Macrophage-stimulating protein induces proliferation and migration of murine keratinocytes. 866 Sep 37

Macrophage stimulating protein (MSP) belongs to the plasminogen-related kringle domain family. In addition to stimulation of macrophages, MSP acts on other cell types including epithelial and hematopoietic cells. The MSP receptor is a transmembrane tyrosine kinase called RON in humans and STK in mice. MSP/receptor interaction induces activation of signal transduction pathways that mediate MSP biological activities. Cytoplasmic kinases are intracellular messengers occupying an important role in signal transduction. We have identified kinases that participate in RON signaling. In addition to previously identified involvement of phosphatidylinositol 3-kinase (PI3-K), JNK, and MAPK, we found that FAK, c-Src, and AKT are rapidly and transiently activated by MSP. FAK, MAPK, and c-Src are involved in MSP-induced cell proliferation. MAPK and c-Src are components of one signal transduction cascade, and MAPK is downstream of c-Src. FAK also regulates MSP-induced cell growth, but via a path different from c-Src/MAPK. AKT kinase is a component of a separate branch of the RON/PI3-K pathway that mediates the MSP anti-apoptotic effect on epithelial cells. PI3-K regulates MSP-induced adhesion and motility but via downstream components different from AKT. Thus, occupancy of the RON receptor by MSP activates distinct signal transduction pathways that mediate several cellular responses.
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PMID:Kinases involved in MSP/RON signaling. 1008 May 38

The human RON gene (MST1R) maps to 3p21.3, a region frequently altered in lung cancer and other malignancies. It encodes a receptor tyrosine kinase (RTK) closely related to MET, whose mutations are associated with neoplasia. We investigated whether RON might be involved in the development or progression of lung cancer. We first determined the exon-intron structure of the gene by direct sequencing of RON cosmid DNA and PCR products containing intronic sequences, and then developed primers suitable for mutation analysis by the single-strand conformation polymorphism (SSCP) method. Twenty coding exons were characterized, all but the first one small (average size: 170 bp), a feature shared with other RTK genes. We performed SSCP analysis of RON in small and non-small cell lung cancer samples, upon detection of its expression in a sample of lung cancer cell lines. A mutation (T915C: L296P) was found in an adenocarcinoma specimen. Several single nucleotide polymorphisms were also found. The panel of intron-anchored primers developed in this work will be useful for mutation analysis of the RON gene in different types of human tumors.
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PMID:Gene structure of the human receptor tyrosine kinase RON and mutation analysis in lung cancer samples. 1095 94

Until now, hepatocytes have been the only known cell source of macrophage-stimulating protein (MSP), and tissue macrophages have been the cells on which the biologic effects of MSP have been proved. To extend the understanding of the biologic meaning of MSP, it was investigated whether MSP operates in the kidney. MSP protein was evaluated by Western blot in supernatant of cultured human tubular cells (HK2) and human mesangial cells (HMC). MSP mRNA was investigated in HK2 by reverse transcription-polymerase chain reaction (RT-PCR). The expression of the MSP receptor, RON, was evaluated in HMC and HK2 by Western blot. RON mRNA was investigated in HMC by RT-PCR. The expression of MSP and RON in normal human renal tissue was studied by immunohistochemistry. HMC were stimulated with recombinant MSP (rMSP) and HK2 supernatant to study cell growth, migration, and the capacity to invade an artificial collagen matrix and synthesize interleukin-6 (IL-6). HK2 produced MSP and expressed RON in a form that was phosphorylated by rMSP. HMC expressed RON but did not produce MSP. MSP in HK2 supernatant and rMSP induced in HMC phosphorylation of RON, growth, migration, invasion, and IL-6 synthesis. In normal human kidney, tubules expressed MSP and RON. These results indicate a novel field of operation for MSP and suggest a pathogenic role of the MSP/RON system in renal disease. In fact, MSP released by tubular cells may recruit monocytes/macrophages in inflammatory tubulointerstitial disorders. In addition, MSP either circulating or as paracrine product may sustain glomerular mesangioproliferative disease.
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PMID:Macrophage-stimulating protein is produced by tubular cells and activates mesangial cells. 1185 68

Macrophage-stimulating protein (MSP) exerts a variety of biological actions on many cell types, but has no known functions in the brain. MSP is structurally related to hepatocyte growth factor (HGF), another pleiotropic factor whose many functions include promoting neuronal survival and growth. To investigate whether MSP is also capable of acting as a neurotrophic factor, we purified hypoglossal motoneurons from the embryonic chicken hindbrain because these neurons are known to express the MSP receptor tyrosine kinase RON. MSP promoted the in vitro survival of these neurons during the period of naturally occurring neuronal death and enhanced the growth of neurites from these neurons. MSP mRNA was detected in the developing tongue whose musculature is innervated by hypoglossal neurons. Our study demonstrates that MSP is a neurotrophic factor for a population of developing motoneurons.
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PMID:Macrophage-stimulating protein is a neurotrophic factor for embryonic chicken hypoglossal motoneurons. 1186 May 10

During sexual reproduction in most animals, oocytes arrest in meiotic prophase and resume meiosis (meiotic maturation) in response to sperm or somatic cell signals. Despite progress in delineating mitogen-activated protein kinase (MAPK) and CDK/cyclin activation pathways involved in meiotic maturation, it is less clear how these pathways are regulated at the cell surface. The Caenorhabditis elegans major sperm protein (MSP) signals oocytes, which are arrested in meiotic prophase, to resume meiosis and ovulate. We used DNA microarray data and an in situ binding assay to identify the VAB-1 Eph receptor protein-tyrosine kinase as an MSP receptor. We show that VAB-1 and a somatic gonadal sheath cell-dependent pathway, defined by the CEH-18 POU-class homeoprotein, negatively regulate meiotic maturation and MAPK activation. MSP antagonizes these inhibitory signaling circuits, in part by binding VAB-1 on oocytes and sheath cells. Our results define a sperm-sensing control mechanism that inhibits oocyte maturation, MAPK activation, and ovulation when sperm are unavailable for fertilization. MSP-domain proteins are found in diverse animal taxa, where they may regulate contact-dependent Eph receptor signaling pathways.
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PMID:An Eph receptor sperm-sensing control mechanism for oocyte meiotic maturation in Caenorhabditis elegans. 1253 8

The candidate tumor-suppressor gene hyaluronidase 2 (HYAL2) encodes a glycosylphosphatidylinositol-anchored cell-surface protein that serves as an entry receptor for jaagsiekte sheep retrovirus, a virus that causes contagious lung cancer in sheep that is morphologically similar to human bronchioloalveolar carcinoma. The viral envelope (Env) protein alone can transform cultured cells, and we hypothesized that Env could bind and sequester the HYAL2 receptor and thus liberate a potential oncogenic factor bound and negatively controlled by HYAL2. Here we show that the HYAL2 receptor protein is associated with the RON receptor tyrosine kinase (also called MST1R or Stk in the mouse), rendering it functionally silent. In human cells expressing a jaagsiekte sheep retrovirus Env transgene, the Env protein physically associates with HYAL2. RON liberated from the association with HYAL2 becomes functionally active and consequently activates the Akt and mitogen-activated protein kinase pathways leading to oncogenic transformation of immortalized human bronchial epithelial cells. We find activated RON in a subset of human bronchioloalveolar carcinoma tumors, suggesting RON involvement in this type of human lung cancer.
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PMID:Hyaluronidase 2 negatively regulates RON receptor tyrosine kinase and mediates transformation of epithelial cells by jaagsiekte sheep retrovirus. 1267 86

The cytokine Macrophage Stimulating 1 (MST1/MSP/Hepatocyte Growth Factor-Like) is a ligand of the Met-related MST1-Receptor (MST1R/RON). Although MST1-deficient mice are viable, MST1R is essential in mice before gastrulation for implantation, and is a known oncogene in man. Here I report the identification, sequence, chromosomal location and embryonic expression of a novel zebrafish orthologue, termed macrophage stimulating 1 (mst1). mst1 shows a striking restriction of expression to the dorsal side of the embryo prior to gastrulation, and as gastrulation and somitogenesis proceed is expressed sequentially in the presumptive neurectoderm, the notochord, the somites, endodermal cells and in the syncytial yolk. This dynamic pattern is largely conserved in tetrapod vertebrates, suggesting that the appearance of MST1, may have played an early role in the evolution of the vertebrate body plan.
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PMID:Identification and developmental expression of a macrophage stimulating 1/ hepatocyte growth factor-like 1 orthologue in the zebrafish. 1276 15

The MST1R (RON) gene, that maps at 3p21.3, encodes a protein tyrosine kinase receptor comprised of an extra-cellular domain that contains the ligand binding pocket and an intracellular region where the kinase domain is located. It controls cell survival and motility programs related to invasive growth. With the single strand conformation polymorphism (SSCP) method, a C to A nucleotide polymorphism (SNP) was found in intron 18 of the gene. The SNP has a frequency of 0.28 among African-American, 0.25 among Caucasian CEPH and 0.09 among Asian healthy individuals. During these studies, an alternatively spliced cDNA of MST1R, lacking exon 19, was also found that may result from this change.
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PMID:C to A single nucleotide polymorphism in intron 18 of the human MST1R (RON) gene that maps at 3p21.3. 1278 25

Hepatocyte growth factor (HGF) is a promoter of hair follicle growth. We examined another HGF family member, macrophage-stimulating protein (MSP), for its hair follicle-modulating properties. Western blotting revealed presence of mature MSP in cultured human dermal papilla (DP) cells and bulbar dermal sheath (DS) cells, but not non-bulbar DS cells. Immunohistology demonstrated expression of MSP receptor RON in the outer and inner root sheaths, hair matrix cells, DP, and bulbar DS whereas non-follicular epithelium and some cells of the sweat glands exhibited low-level receptor expression. Human hair follicles exposed in vitro for 8 d to 0.1, 1, 10, and 100 ng per mL MSP all yielded a mean net increase in hair follicle length in excess of the mean baseline growth observed in controls. MSP was incubated with agarose beads and injected subcutaneously into mice all 70 d old when a uniform telogen state in dorsal skin was apparent. All eight mice receiving 1 microg MSP, and four of eight receiving 100 ng MSP showed induction of anagen hair growth at the site of bead implantation by 16 d whereas eight mice implanted with saline incubated beads had no hair growth. The data identify MSP as a modulator of hair growth.
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PMID:Macrophage-stimulating protein promotes hair growth ex vivo and induces anagen from telogen stage hair follicles in vivo. 1519 39


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