Model organisms: New insights into ion channel and transporter function. Stomatin homologues interact in Caenorhabditis elegans

In C. elegans the protein UNC-1 is a major determinant of anesthetic sensit ivity and is a close homologue of the mammalian protein stomatin. In humans stomatin is missing from erythrocyte membranes in the hemolytic disease ov erhydrated hereditary stomatocytosis, despite an apparently normal stomatin gene. Overhydrated hereditary stomatocytosis is characterized by alteratio n of the normal transmembrane gradients of sodium and potassium. Stomatin h as been shown to interact genetically with sodium channels. It is also post ulated that stomatin is important in the organization of lipid rafts. We de monstrate here that antibodies against UNC-1 stain the major nerve tracts o f Caenorhabditis elegans, with very intense staining of the nerve ring. We also found that a gene encoding a stomatin-like protein, UNC-24, affects an esthetic sensitivity and is genetically epistatic to unc-1. In the absence of UNC-24, the staining of the nerve ring by anti-UNC-1 is abolished, despi te normal transcriptional levels of the unc-1 mRNA. Western blots indicate that UNC-24 probably affects the stability of the UNC-1 protein. UNC-24 may therefore be necessary for the correct placement of UNC- 1 in the cell mem brane and organization of lipid rafts.