Figure - PMC

Skip to main content

An official website of the United States government

Here's how you know

Here's how you know

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

View full-text article in PMC

. 2013 Aug 5;202(3):527–543. doi: 10.1083/jcb.201211045

Search in PMC
Search in PubMed
View in NLM Catalog
Add to search

© 2013 Allison et al.

This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

PMC Copyright notice

Figure 6. — Spastin is required for sorting TfnR away from degradation. (a and b) Mock-transfected HeLa cells or HeLa cells transfected with a pool of spastin siRNA (spastin knockdown [KD]) were immunoblotted for the antibodies indicated. TfnR band density was quantified, and the mean density in three independent experiments was plotted in b. (c and d) Mock-transfected HeLa cells or HeLa cells transfected with a pool of spastin siRNA were treated with vehicle (DMSO) or DMSO + bafilomycin and then immunoblotted versus the antibodies indicated. TfnR band density was quantified, and the mean density in eight independent experiments was plotted in d. (e–g) Confocal micrographs of HeLa cells subjected to mock transfection (e) or transfected with a spastin siRNA pool (f and g) and then labeled with the markers shown. Confocal micrograph gain settings were identical in e and f, but in g, which shows a higher magnification image of the dashed area indicated in f, gain settings were increased to reveal that the remaining TfnR signal strongly colocalized with M6PR. Note that tubular TfnR structures are not readily seen under confocal microscopy, as the tubules tend to leave the plane of section. Insets are magnified regions of the boxed areas. (h) Mock-transfected HeLa cells or HeLa cells transfected with a pool of spastin siRNA were fixed and labeled (without permeabilization) with a FITC-conjugated antibody against TfnR, and then, the cell-associated fluorescent signal was quantified by FACS analysis. The mean fluorescence values for three independent experiments were plotted. (i–k) Uptake of Alexa Fluor 647–conjugated Tfn was measured by FACS over a 20-min time course in mock-transfected HeLa cells, cells transfected with siRNA targeting clathrin heavy chain (CHC), or cells transfected with one of two siRNAs directed against spastin (spas1, spastin 1; spas3, spastin 3). Mean Tfn uptake at the 20-min time point (n = 3 experiments) is shown in i, and a representative time course experiment is shown in j. Depletion of the relevant proteins targeted by siRNA was confirmed by immunoblotting, and a representative example is shown in k. (l and m) Recycling of internalized fluorescently labeled Tfn was measured over a 20-min time course, and the mean cell-associated Tfn at the 20-min time point (n = 3 experiments) is shown in l, with a representative time course experiment shown in m. Bars, 10 µm. Error bars show SEMs.