Amniotic membrane attracts and traps inflammatory cells infiltrating the ocular surface, which may explain some of the antiinflammatory properties of the fetal tissue.

A novel mouse macrophage galactose-type C-type lectin 2 (mMGL2) was identified by BLAST analysis of expressed sequence tags. The sequence of mMGL2 is highly homologous to the mMGL, which should now be called mMGL1. The open reading frame of mMGL2 contains a sequence corresponding to a type II transmembrane protein with 332 amino acids having a single extracellular C-type lectin domain. The 3-untranslated region included long terminal repeats of mouse early transposon. The Mgl2 gene was cloned from a 129/SvJ mouse genomic library and sequenced. The gene spans 7,136 base pairs and consists of 10 exons, which is similar to the genomic organization of mMGL1. The reverse transcriptase-PCR analysis indicates that mMGL2 is expressed in cell lines and normal mouse tissues in a macrophage-restricted manner, also very similar to that of mMGL1. The mMGL2 mRNA was also detected in mMGL1-positive cells, which were sorted from thioglycollate-induced peritoneal cells with a mMGL1-specific monoclonal antibody, LOM-8.7. The soluble recombinant proteins of mMGL2 exhibited carbohydrate specificity for ␣-and ␤-GalNAc-conjugated soluble polyacrylamides, whereas mMGL1 preferentially bound Lewis X-conjugated soluble polyacrylamides in solid phase assays. These two lectins may function cooperatively as recognition and endocytic molecules on macrophages and related cells. Macrophages (MØs)1 and related cells are widely distributed throughout the body, displaying a morphological and functional diversity. They are found in the lymphoid organs, liver, lungs, gastrointestinal tract, central nervous system, serous cavities, bones, synovia, and skin. Resident MØs mediate clearance of senescent or apoptotic cells, produce and secrete cytokines, are involved in hemopoiesis and bone resorption, transport and present antigens, and regulate neuroendocrine processes. Activated MØs are recruited to sites of infection, tissue injury, inflammation, and neoplasia and play crucial roles in tissue repair and pathogenesis (1).The distribution and functional heterogeneity of MØs derive in part from their specialized plasma membrane receptors (2). Cell surface markers such as F4/80, sialoadhesin, MØ mannose receptor and scavenger receptor type A have significantly contributed to the current understanding of MØ ontogeny and function (3). However, in comparison to other immune cells such as B and T lymphocytes, relatively few MØ-restricted cell surface molecules have been identified. The physiological and pathological roles of these putative markers remain unknown.Protein-carbohydrate interactions serve a variety of functions in the immune system. A number of lectins (carbohydrate-binding proteins) mediate both pathogen recognition and cell-to-cell interactions using structurally related carbohydrate recognition domains (CRDs). One of the most diversified families of these CRDs is Ca 2ϩ -dependent and termed C-type CRDs (4, 5). MØs and related cells such as dendritic cells are known to express several subfamilies of C-type lectins: type 1 multilectins such as...

Background: Golgi is a potential target for cancer treatment, but no inhibitor became an anticancer drug.Results: Using a unique bioinformatics approach, we identified a novel Golgi inhibitor, AMF-26, targeting Arf1 activation and possessing potent antitumor activity.Conclusion: AMF-26 is a promising new anticancer drug lead.Significance: Our data indicate that Arf1 activation is a promising target for cancer treatment.

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Arf GTPases and their guanine nucleotide exchange factors (ArfGEFs) are major regulators of membrane traffic and organelle structure in cells. They are associated with a variety of diseases and are thus attractive therapeutic targets for inhibition by small molecules. Several inhibitors of unrelated chemical structures have been discovered, which have shown their potential in dissecting molecular pathways and blocking disease-related functions. However, their specificity across the ArfGEF family has remained elusive. Importantly, inhibitory responses in the context of membranes, which are critical determinants of Arf and ArfGEF cellular functions, have not been investigated. Here, we compare the efficiency and specificity of four structurally distinct ArfGEF inhibitors, Brefeldin A, SecinH3, M-COPA, and NAV-2729, toward six ArfGEFs (human ARNO, EFA6, BIG1, and BRAG2 and Legionella and Rickettsia RalF). Inhibition was assessed by fluorescence kinetics using pure proteins, and its modulation by membranes was determined with lipidated GTPases in the presence of liposomes. Our analysis shows that despite the intra-ArfGEF family resemblance, each inhibitor has a specific inhibitory profile. Notably, M-COPA is a potent pan-ArfGEF inhibitor, and NAV-2729 inhibits all GEFs, the strongest effects being against BRAG2 and Arf1. Furthermore, the presence of the membrane-binding domain in Legionella RalF reveals a strong inhibitory effect of BFA that is not measured on its GEF domain alone. This study demonstrates the value of family-wide assays with incorporation of membranes, and it should enable accurate dissection of Arf pathways by these inhibitors to best guide their use and development as therapeutic agents.