The endoplasmic reticulum remains functionally connected by vesicular transport following its fragmentation in cells expressing Z-α1-antitrypsin

Duration: 1 min 8 secs

Share this media item:

Embed this media item:

<iframe width="_width_" height="_height_" src="https://sms.cam.ac.uk/media/2331570/embed" frameborder="0" scrolling="no" allowfullscreen></iframe>

Choose size:

About this item

Available Formats

About this item

Description:	An inclusion-laden CHO cell transfected with YFP-Z-α1-antitrypsin and selected using fluorescence microscopy was subjected to electron microscopy. The peripheries of Z-α1-antitrypsin containing inclusions were recorded manually in each 2D micrograph and combined using Imaris software to generate a 3D projection by isosurface rendering.


Created:	2016-10-03 18:09
Collection:	Energy@Cambridge
Publisher:	University of Cambridge
Copyright:	Stefan J. Marciniak
Language:	eng (English)
Keywords:	α1-antitrypsin;


Abstract:	Alpha-1-antitrypsin is a serine protease inhibitor produced in the liver that is responsible for the regulation of pulmonary inflammation. The commonest pathogenic gene mutation yields Z-α1-antitrypsin, which has a propensity to self-associate forming polymers that become trapped in inclusions of endoplasmic reticulum (ER). It is unclear whether these inclusions are connected to the main ER network in Z-α1-antitrypsin-expressing cells. Using live cell imaging, we show that despite inclusions containing an immobile matrix of polymeric α1-antitrypsin, small ER resident proteins can diffuse freely within them. Inclusions have many features to suggest they represent fragmented ER and some are physically separated from the tubular ER network, yet we observe cargo to be transported between them in a cytosol-dependent fashion that is sensitive to NEM and dependent on Sar1 and sec22B. We conclude that protein recycling occurs between ER inclusions despite their physical separation.

Abstract:

Alpha-1-antitrypsin is a serine protease inhibitor produced in the liver that is responsible for the regulation of pulmonary inflammation. The commonest pathogenic gene mutation yields Z-α1-antitrypsin, which has a propensity to self-associate forming polymers that become trapped in inclusions of endoplasmic reticulum (ER). It is unclear whether these inclusions are connected to the main ER network in Z-α1-antitrypsin-expressing cells. Using live cell imaging, we show that despite inclusions containing an immobile matrix of polymeric α1-antitrypsin, small ER resident proteins can diffuse freely within them. Inclusions have many features to suggest they represent fragmented ER and some are physically separated from the tubular ER network, yet we observe cargo to be transported between them in a cytosol-dependent fashion that is sensitive to NEM and dependent on Sar1 and sec22B. We conclude that protein recycling occurs between ER inclusions despite their physical separation.

Available Formats

Format	Quality	Bitrate	Size
MPEG-4 Video	480x360	918.96 kbits/sec	7.63 MB	View	Download
WebM	480x360	384.22 kbits/sec	3.19 MB	View	Download
iPod Video	480x360	395.52 kbits/sec	3.28 MB	View	Download
Auto *	(Allows browser to choose a format it supports)