Fig. 6: Sec14L6 deficiency impaired PIP homeostasis of the ER and LD.

a Membrane fractionation showing the purity of the ER or LD fractions used in the lipidomic analyses from at least 3 independent experiments. Western blots were performed with antibodies against Plin2 (LD marker), VAPB (ER marker), Lamp1 (late endosome/PM marker), E-cadherin (PM marker), VDAC1 (mitochondrial marker), GM130 (Golgi marker) and GAPDH (cytosol marker). The levels of PIPs (b), including PI4P (c) and PI(4,5)P₂ (d) in the LD fraction from control or Sec14L6 KO-2 HeLa cells from three biological replicates. In (c, d), top 10 lipid species based on abundance were shown. Two-tailed unpaired Student’s t test. Mean ± SD. The levels of other glycerophospholipids (e), including PS (f) and PC (g) in the LD fraction from control or Sec14L6 KO-2 HeLa cells from three biological replicates. In (f, g), top 10 lipid species based on abundance were shown. Two-tailed unpaired Student’s t test. Mean ± SD. The levels of PIPs (h), including PI4P (i) and PI(4,5)P₂ (j) in the ER fraction from control or Sec14L6 KO-2 HeLa cells from three biological replicates. In (i, j), top 10 lipid species based on abundance were shown. Two-tailed unpaired Student’s t test. Mean ± SD. The levels of other glycerophospholipids (k), including PC (l), PS (m) and PI (n) in the ER fraction from control or Sec14L6 KO-2 HeLa cells from three biological replicates. In (l, m, n), top 10 lipid species based on abundance were shown. Two-tailed unpaired Student’s t test. Mean ± SD. o Representative dot blot assay showing cellular PI4P levels in the ER fraction (left panel), LD fractions (middle panel) or whole cell lysate (right panel) from WT or Sec14L6 KO-2 HeLa cells using PI4P antibody from 3 independent experiments. VAPB, Plin2 and GAPDH are used as the load control for the ER, LD or whole cell lysate, respectively, shown on the bottom.