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Hemese, a hemocyte-specific transmembrane protein, affects the cellular immune response in Drosophila

2003; National Academy of Sciences; Volume: 100; Issue: 5 Linguagem: Inglês

10.1073/pnas.0436940100

1091-6490

Éva Kurucz, Carl Johan Zettervall, Rita Sinka, Péter Vilmos, Andor Pivarcsi, Sophia Ekengren, Zoltán Hegedüs, István Andó, Dan Hultmark,

Neurobiology and Insect Physiology Research

We have identified a previously undescribed transmembrane protein, Hemese, from Drosophila melanogaster blood cells (hemocytes), by using a monoclonal pan-hemocyte antibody. Heavy glycosylation is suggested by the heterogeneous size distribution, ranging between 37 and 70 kDa. Hemese expression is restricted to the cell surfaces of hemocytes of all classes, and to the hematopoietic organs. The sequence of the corresponding gene, Hemese ( He ), predicts a glycophorin-like protein of 15 kDa, excluding an N-terminal signal peptide, with a single hydrophobic transmembrane region. The extracellular region consists mainly of Ser/Thr-rich sequence of low complexity, with several potential O-glycosylation sites. Hemese contains phosphotyrosine and the cytoplasmic region has potential phosphorylation sites, suggesting an involvement in signal transduction. Depletion of Hemese by RNA interference has no obvious effect under normal conditions, but the cellular response to parasitic wasps is much enhanced. This finding indicates that Hemese plays a modulatory role in the activation or recruitment of the hemocytes.