The AC invasive membrane and protrusion is enriched with lipid-modified proinvasive proteins. (A) Top: A schematic diagram of AC invasion. Bottom: Merged differential interference microscopy (DIC) and fluorescence images (maximum intensity z-projections) showing the AC (cyan, mCherry::PLCδ^PH), the underlying BM (magenta, LAM-1:GFP), and the vulval precursor cells (VPCs, DIC). The AC is specified at the L2/L3 molt and proinvasive gene expression occurs at the P6.p 1-cell stage. AC invasion is initiated at the late P6.p 2-cell stage when an invadosome breaches the BM. During the P6.p 2–4-cell transition, a large invasive protrusion forms at the breach site that expands the BM gap and then retracts, allowing the AC to contact the central VPCs at the P6.p 4-cell stage. Timeline in hours after hatching at 20°C is shown. (B–D) In the AC of wild-type animals, the GPI-anchored matrix metalloproteinase ZMP-1 (ZMP-1::mNG), (C) lysosomes (LMP-1::mNG), (D) and the prenylated membrane reporter (GFP::CAAX), prenylated Rac GTPases (GFP::CED-10 and GFP::MIG-2), and Ras-like GTPase RAP-1 (mNG::RAP-1) are enriched at the AC basal plasma membrane prior to invasion (arrows; P6.p 2-cell stage) and within the AC invasive protrusion (arrowheads; P6.p 2–4-cell stage) (observed in n ≥ 10 animals for each). All data shown are from two or more replicates. Scale bars, 5 µm.