Disease relevance of METAP2

• Model building established that human MetAP (p67) could be readily accommodated into the Escherichia coli MetAP structure and that the Co2+ ligands were fully preserved [1].
• High expression of methionine aminopeptidase 2 in human colorectal adenocarcinomas [2].
• To dissect p67-PKR interactions and evaluate their significance in vivo, we have used a vaccinia virus (VV) expression system that successfully mimics PKR control pathways [3].
• Long antisense, as well as RNAi for p67, delivered into Karpas299 cells by adenoviruses, reduced p67 levels [4].
• Methionine aminopeptidase-2 regulates human mesothelioma cell survival: role of Bcl-2 expression and telomerase activity [5].

High impact information on METAP2

• Fumagillin-based drugs inhibit MetAP-2 but not MetAP-1, and the three-dimensional structure also indicates the likely determinants of this specificity [6].
• The molecular target of fumagillin is methionine aminopeptidase-2 (MetAP-2) [6].
• A 1.8 A resolution crystal structure of free and inhibited human MetAP-2 shows a covalent bond formed between a reactive epoxide of fumagillin and histidine-231 in the active site of MetAP-2 [6].
• To confirm the role of MetAP-2 in endothelial cell proliferation and to validate it as a physiological target for the Fg class of antiangiogenic agents, we have generated a conditional MetAP-2 knockout mouse [7].
• Together, these results demonstrate an essential role for MetAP-2 in angiogenesis and indicate that MetAP-2 is responsible for the endothelial cell growth arrest induced by Fg and its derivatives [7].

Chemical compound and disease context of METAP2

• Here, we report that PPI-2458, a novel, orally active agent of the fumagillin class of irreversible methionine aminopeptidase-2 (MetAP-2) inhibitors, potently inhibited the proliferation of B16F10 melanoma cells in vitro, with a growth inhibitory concentration 50% (GI50) of 0.2 nM [8].

Biological context of METAP2

• This cDNA sequence is highly similar to a rat protein, termed p67, which was identified as an inhibitor of phosphorylation of initiation factor eIF2 alpha and was previously predicted to be a metallopeptidase based on limited sequence homology [1].
• Previously, we cloned a human cDNA encoding a protein which has a 92% amino acid sequence identity to a rat initiation factor-2 associated protein (p67) [9].
• Using 13 different peptide substrates, we found that the human p67 has a similar substrate specificity with other MetAPs [9].
• The most potent of these compounds contained a singly-substituted triazole moiety which exhibited an IC50 of 8 nM (95% confidence limits 5 to 13 nM) and was highly selective for MetAP-2 over MetAP-1 (approximately 60-fold difference in IC50 values) [10].
• Stable expression of p67 reduced the PKR-mediated antiviral response and apoptosis [3].

Anatomical context of METAP2

• Unlike fumagillin, these MetAP-2 inhibitors failed to significantly inhibit growth factor-stimulated endothelial cell (HUVEC) proliferation or to suppress angiogenesis in the in vitro aortic ring explant model of microvessel outgrowth [10].
• The plant protein (termed PKI) specifically cross-reacts with monoclonal antiserum that recognizes the glycosylated, active form of a M(r) 87 kD protein analog (p67) from reticulocytes [11].
• (1) Transient transfection of COS-1 cells with a p67 expression vector increased p67 synthesis by 20-fold over endogenous levels in the isolated subpopulation of transfected cells [12].
• This study looked for the effect of 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase inhibitors on NADPH oxidase-dependent superoxide anion production in THP-1 cells, a monocyte-derived cell line, and on the translocation of p21 Rac 2 and p67 [13].
• One of the proteins found to be increased in the cerebrospinal fluid of OPG-bearing mice was the eukaryotic initiation factor-2alpha binding protein, methionine aminopeptidase 2 (MetAP2) [14].

Associations of METAP2 with chemical compounds

• Here we report that S100A4 physically interacts with methionine aminopeptidase 2 (MetAP2), the primary target for potent angiogenesis inhibitors, fumagillin and ovalicin [15].
• Structure of human methionine aminopeptidase-2 complexed with fumagillin [6].
• We describe here the crystal structure of hMetAP-2 in complex with l-methionine and d-methionine at 1.9 and 2.0A resolution, respectively [16].
• These results support the recent hypothesis that cobalt may not be the relevant divalent metal ion cofactor for MetAP-2 in cells and may explain the observed absence of cell-based activity using potent triazole inhibitors of cobalt-activated MetAP-2 [10].
• When manganese (Mn2+) was substituted for cobalt following EDTA treatment and extensive dialysis of the MetAP-2 protein, these inhibitors were significantly less potent (40-fold increase in IC50) as inhibitors of MetAP-2 [10].

Regulatory relationships of METAP2

• Recombinant VV were constructed that constitutively express p67 and inducibly express PKR in BSC-40 cells [3].
• (3) Overexpression of p67 reduced phosphorylation of coexpressed eIF-2 alpha [12].

Other interactions of METAP2

• Expression of methionine aminopeptidase 2, N-myristoyltransferase, and N-myristoyltransferase inhibitor protein 71 in HT29 [17].
• However, when eIF-2 was preincubated specifically with the eIF-2 gamma-subunit antibodies, subsequent co-immunoprecipitation of p67 with the eIF-2 subunits was completely inhibited [18].
• Other potential genes responsible for intellectual deficiency disrupted as a result of patient's chromosomal rearrangement map at 12q14.1 (TAFA2), 12q23.1 (METAP2), and 11p14.1 (BDNF) [19].
• The reduction in p67 levels led to increased phosphorylation of eIF2alpha, and an additive effect was achieved by coinfection with NPM/ALK-AS encoding adenoviruses [4].
• In addition, simvastatin inhibited the translocation of p21 rac 2 and p67, suggesting that geranylgeranylation is required for NADPH oxidase activation [13].

Analytical, diagnostic and therapeutic context of METAP2

• Molecular cloning of a human complementary DNA encoding an initiation factor 2-associated protein (p67) [20].
• Studies from yeast two-hybrid assays show that p67 interacts strongly with eIF2gamma, relatively weakly with eIF2alpha, and no interaction with eIF2beta [21].
• Finally, inhibition of MetAP-2 and proliferation by PPI-2458 was examined in the human SR NHL line in culture and in implanted xenografts [22].
• Immunohistochemical and Western immunoblot analysis of normal human brain tissue using antibodies against the N- and C-termini of p67 demonstrated the specific localization of this protein in postmitotic neurons but not in glia [23].
• Earlier, in situ hybridization and immunocytochemical analysis of rat trigeminal ganglion and hippocampal cells demonstrated the specific localization of p67 in nerve cells and its rich distribution in axons [23].

References