DMIM is the Drosophila homologue of human MIM. (A) The genomic structure of the dmim locus on chromosome 2R, 42C-42E, showing the transcriptional start (arrow) and exons encoding the I-BAR, scaffolding, and WH2 domains. The black box above indicates the exons (3–10) deleted by homologous recombination to make dmim-null flies. (B) Native gel of hMIM, DMIM, or DMIM mutant (4KA) I-BAR domains binding with lipids. Only when the I-BAR domain(s) bind to lipids will they run down the native gel. (C) hMIM, DMIM, or DMIM mutant (4KA) I-BAR domain cosedimented with PI(4,5)P2- or PI(3,4,5)P3-rich (30%) large multilamellar vesicles. Human and fly MIM display similar specificity in binding for specific lipids. (D) Overexpressing human or Drosophila MIM in Drosophila S2 cells results in similar changes in the actin cytoskeleton. Overexpression of either protein results in the formation of actin-based protrusions from the cell membrane. Bar = 20 µm.