The G3 domain is essential for Ndg function.

(A) Confocal images showing localization in fat body BM of the indicated GFP-tagged versions of Ndg, detected by GFP signal (white), in wild type (left column) and upon knock down of laminin (LanAi, middle column) and Collagen IV (Cg25Ci, right column). (B, C) Quantification of GFP signal intensity of indicated GFP-tagged Ndg versions in the BM of wild type control, LanAi (B) and Cg25Ci (C) fat body. Each dot represents a single measurement of intensity inside a 500μm2 square. Horizontal lines indicate the mean value (****: pMaterials and Methods for statistical testing details. (D) Confocal images of the larvae fat body BM (Cg25C.RFP in red) in control, Ndg1 mutant, and Ndg1 mutant expressing NdgΔG1, NdgΔG2 or NdgΔG3. Integrity of the BM is restored by NdgΔG1 and NdgΔG2 but not NdgΔG3. (E) Confocal images showing uncoupling of Collagen IV (Cg25C.RFP in red, middle panels) and Laminin (LanB1.sGFP in cyan, right panels) in Ndg1 mutant (lower panels) and wild type fat body (upper panels). Merged channels are shown in left panels. (F) Confocal images of Collagen IV (Cg25C.RFP in red, middle panels) and Perlecan (Trol.GFP in green, right panels) in Ndg1 mutant (lower panels) and wild type fat body (upper panels). Merged channels are shown in left panels. (G) Quantification of Pearson’s colocalization coefficient after Costes thresholding (R coloc) of Collagen IV with Laminin (E) and Collagen IV with Perlecan (F). (H) Model for the role of the G1, G2 and G3 domains on Ndg binding to Laminin and Collagen IV.