Fig 1: Molecular interactions at LD-APM contacts. Representative images of XOR (green/monochrome) or Cidea (green/monochrome) and BTN (red/monochrome) immunofluorescence (A) or Rab18 (green/monochrome) and BTN (red/monochrome) immunofluorescence (D) at LD-APM contacts in WT mammary glands following litter removal for 2 h at L10 to inhibit milk secretion. LD in images are indicated by asterisks and outlined by dotted white lines. Blue fluorescence in D is Alexa633-tagged wheatgerm agglutinin staining of the APM glycocalyx. Bar is 10 µ. (B,C,E) Pearson’s correlation coefficients describing immunofluorescence overlap between BTN and XOR (B), BTN and Cidea (C), or BTN and Rab18 (E) in 40–60 sMEC/animal from 3–4 WT and Plin2-Null dams following litter removal for 2 h at L10. Median values are indicated by white bars and average medians ±SEM are shown above each group. p-values for group differences were determined by nested t-test and are shown at the top of each figure. Pearson’s coefficients of 1, 0 and −1 respectively represent perfect positive correlation (Corr), no correlation (Uncorr.) and perfect negative correlation (Anti-corr.).
Fig 2: Milk fat globule membrane (MFGM) protein composition. (A) Volcano plots showing log2 fold change in normalized spectral abundance factor (NSAF) ratios for proteins in WT and Plin2-Null MFGM versus −log10 of their q-values, multiple unpaired t tests with FDR = 1%. For purposes of display, proteins present in WT MFGM but absent in Plin2-Null MFGM were assigned NSAF ratios of 1,000 (Log2 = 10). Proteins present in Plin2-Null MFGM but absent in WT MFGM were assigned NSAF ratios of 0.001 (Log2 = −10). Proteins with q-values ≤ 0.000001 are assigned values of 0.000001 (log10 = 6). WT enriched MFGM proteins are right and Plin2-Null enriched MFGM proteins are left of the vertical dotted line. Proteins found at LD-APM contact sites, BTN, XOR, Cidea and Plin2, are indicated by green diamond symbols. The horizontal line indicates q = 0.01. (B) STRING networks of proteins elevated (q > 0.01) in WT MFGM were identified using Cytoscape 3.9.1. Proteins forming a network with Plin2 include those implicated in formation of LD-APM contacts (XOR, BTN and Cidea) and Rab18 and FABP3. (C) Average ±SEM XOR:BTN and Cidea:BTN NSAF ratios in WT and Plin2-Null MFGM. Asterisk indicates p < 0.05, Students t-test. (D) Average ±SEM Rab18:BTN and Fabp3:BTN NSAF ratios in WT and Plin2-Null MFGM. Asterisk indicates p < 0.05, Students t-test. (E) STRING networks of proteins elevated (q < 0.01) in Plin2-Null MFGM are enriched in ER/chaperone and lipid metabolism proteins.
Supplier Page from Abcam for Anti-Rab18 antibody