Figure 4

Fibronectin is localized to late endosome compartments which require intact tubulin microtubules to traffic to the plasma membrane. (A) To examine inhibitor effects on secretion of FN1, an ELISA assay was performed on tissue culture media (HPC-1) collected from LNCaP cells treated with AUY922 (25 nM) for 48 h and controlled for cell number. Date represents mean ± SEM of  4 independent experiments. (B) Model illustrating cytosolic vesicle and compartment trafficking to the plasma membrane along microtubule networks. (C) Co-location of FN1 with vesicle markers including endosomes (EEA1, Appl1, Rab5, Rab7), lysosome (LIMP2, LAMP1), endoplasmic reticulum (PDI) and Golgi (Tgn46) was examined by fluorescence microscopy in LNCaP cells treated with DMSO for 48 h and probed for vesicle markers (red) and FN-1 (green) and DAPI mount media (blue). Images were taken using Leica SP8 confocal microscope at 63x magnification.