Neuronal growth regulator 1 (NEGR1) has become a great interest based on the recent findings that its genetic alteration is implicated in human obesity and human dyslexia. By analyzing the gene expression profiles of tumor biopsies and normal tissues, we identified NEGR1 as a commonly down-regulated gene in many types of human cancer tissues. NEGR1 contains a C-terminal GPI anchor attachment site and is primarily localized to cell membrane rafts, especially in cell-to-cell contacting areas. The oncogenic phenotype was clearly attenuated when NEGR1 was overexpressed in the human ovarian cancer cell line SKOV-3. Furthermore, cell aggregation and neurite outgrowth was greatly increased by NEGR1 overexpression. On the contrary, cell migration and invasion was increased in NEGR1-depleted cells, suggesting that NEGR1 may contribute to tumor suppression. Taken together, we suggest that NEGR1 is a raft-associated extracellular protein that may participate in cell recognition and interaction, which is important in growth control and malignant transformation.

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Recent studies have shown that global gene expression during oxidative stress in Schizosaccharomyces pombe is regulated by stress-induced activation and binding of Csx1 to atf1 + mRNA. However, the kinase responsible for the activation of Csx1 has not been identified. Here, we describe, for the first time, that Csx1 is phosphorylated by S. pombe LAMMER kinase, Lkh1, under oxidative conditions and that the stressactivated binding of the Csx1 to the atf1 + mRNA was also affected by Lkh1 and Spc1. These data indicate that concerted actions of Spc1 and Lkh1 are required for the activation of Csx1 during oxidative condition in the fission yeast S. pombe.

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Crh1p and Crh2p of Saccharomyces cerevisiae are cell wall proteins covalently attached to cell wall glucan and are thought to be putative glycosidases involved in cell wall remodelling. We investigated whether YlCrh1p and YlCrh2p, the Yarrowia lipolytica proteins homologous to ScCrh1p and ScCrh2p, had the required glycosidase activity for cell wall biosynthesis and maintenance. Ylcrh1 and Ylcrh2 mutants showed sensitivity to compounds that interfere with cell wall construction. Soluble forms of YlCrh1p and YlCrh2p that lacked the C-terminal consensus sequence for GPI anchoring showed glycosidase activity on laminarin, a substrate carrying β-1,3-glycosidic linkage. Our study suggests that the YlCrh1p and YlCrh2p may participate in cell wall biosynthesis and remodelling through their β-1,3-glycosidase activity.