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. Author manuscript; available in PMC: 2010 Aug 1.
Published in final edited form as: Front Neuroendocrinol. 2009 May 4;30(3):315–327. doi: 10.1016/j.yfrne.2009.04.011

Figure 1. E-6-BSA-FITC and E-6-biotin are internalized in primary cortical neurons.

Figure 1

(A) Ligand bound receptors are internalized and transported to endosomes to be sorted for recycling or degradation by a β-arrestin mediated mechanism. (B) Cortical neuronal cultures were prepared on glass coverslips and treated with 1 μg/ml E-6-BSA-FITC for 60 min at 37 °C, fixed, and prepared for confocal microscopy. Analysis of reconstructed confocal z-stack slices (side panels) show that E-6-BSA-FITC binding was localized on plasma membranes (arrowheads) and within subcellular compartments (arrows) in several neuronal profiles. (C) Cortical neurons were prepared as described above but were treated with 50 nM E-6-biotin and permeablized after fixation. Biotin conjugated-estradiol was labeled with 1 mg/ml Alexa488-strepavidin to visualize internalization of the ligand. Reconstructed confocal z-stack slices (side panels) demonstrate that the fluorescein labeled E-6-biotin/strepavidin complex was internalized in a similar manner as E-6-BSA-FITC in several neuronal profiles. These findings suggest ligand bound ERs are internalized. Scale bar = 20 μm. [these data redrawn from 42]