The University of Southampton
University of Southampton Institutional Repository

The biochemistry of serpin secretion : an investigation into the effects of mutant and corrective variants

The biochemistry of serpin secretion : an investigation into the effects of mutant and corrective variants
The biochemistry of serpin secretion : an investigation into the effects of mutant and corrective variants

FENIB diseases are a distinct class of dementia pathologies, which show deposition of polymerised neuroserpin (P112, SERPIN1) in structures known as Collins’ bodies, which leads to the death of the synthesizing cells.  Another feature of the diseases is the loss of neurons from well defined areas thought to arise from a deficiency of the neuroserpin.

There are four natural mutations in the neuroserpin gene that lead to these FENIB pathologies:  Syracuse - S249P is the equivalent mutation to α1-AntitrypsinSilymama, which is at the commencement of the sheet-opening domain, Portland - S52R, H338R & G392E.  These mutations are all within the shutter domain, a domain that is structurally important to the activity of all inhibitory serpins.  All four mutants are autosomal dominant and lead to pathological phenotypes that can be ordered in severity:  S49P<S52R<H338R<G392E.

We have examined the secretion of these four mutant forms of neuroserpin and compared it to that of the normal variant protein using the Xenopus oocyte system.  The time-course of secretion for normal variant neuroserpin in comparison to that of another serpin, wildtype α1-antitrypsin was also studied.

58.1% (±6.4) of normal variant neuroserpin is secreted from oocytes microinjected with wildtype mRNA, slightly lower than seen in previous expression of M variant α1-antitrypsin (63%).  All mutant variants reduce secretion:  S49P 11.1% (±3.9) S52R 13.9% (±3.5), H338R 15.1%, G392E 9.9%, Y34S 2.2% (±2.1).  Neuroserpin wildtype has a slower initial secretion than α1-AT which is maybe due to the polarised nature of secretion and could be directed by novel signalling motifs.

Using chemical and physical dissection, the intracellular location of the polymers visualised within this system was determined to be the ER.  Endo H resistance was not inferred on oocyte extracts suggesting that accumulation occurs within a pre-Golgi compartment, with tunicamycin treatment showing that glycosylation is required for successful secretion but has no direct effect on polymerisation.

University of Southampton
Ravenhill, Neil A
f621445e-342a-4430-8c83-591314fd8bdb
Ravenhill, Neil A
f621445e-342a-4430-8c83-591314fd8bdb

Ravenhill, Neil A (2004) The biochemistry of serpin secretion : an investigation into the effects of mutant and corrective variants. University of Southampton, Doctoral Thesis.

Record type: Thesis (Doctoral)

Abstract

FENIB diseases are a distinct class of dementia pathologies, which show deposition of polymerised neuroserpin (P112, SERPIN1) in structures known as Collins’ bodies, which leads to the death of the synthesizing cells.  Another feature of the diseases is the loss of neurons from well defined areas thought to arise from a deficiency of the neuroserpin.

There are four natural mutations in the neuroserpin gene that lead to these FENIB pathologies:  Syracuse - S249P is the equivalent mutation to α1-AntitrypsinSilymama, which is at the commencement of the sheet-opening domain, Portland - S52R, H338R & G392E.  These mutations are all within the shutter domain, a domain that is structurally important to the activity of all inhibitory serpins.  All four mutants are autosomal dominant and lead to pathological phenotypes that can be ordered in severity:  S49P<S52R<H338R<G392E.

We have examined the secretion of these four mutant forms of neuroserpin and compared it to that of the normal variant protein using the Xenopus oocyte system.  The time-course of secretion for normal variant neuroserpin in comparison to that of another serpin, wildtype α1-antitrypsin was also studied.

58.1% (±6.4) of normal variant neuroserpin is secreted from oocytes microinjected with wildtype mRNA, slightly lower than seen in previous expression of M variant α1-antitrypsin (63%).  All mutant variants reduce secretion:  S49P 11.1% (±3.9) S52R 13.9% (±3.5), H338R 15.1%, G392E 9.9%, Y34S 2.2% (±2.1).  Neuroserpin wildtype has a slower initial secretion than α1-AT which is maybe due to the polarised nature of secretion and could be directed by novel signalling motifs.

Using chemical and physical dissection, the intracellular location of the polymers visualised within this system was determined to be the ER.  Endo H resistance was not inferred on oocyte extracts suggesting that accumulation occurs within a pre-Golgi compartment, with tunicamycin treatment showing that glycosylation is required for successful secretion but has no direct effect on polymerisation.

Text
968451.pdf - Version of Record
Available under License University of Southampton Thesis Licence.
Download (53MB)

More information

Published date: 2004

Identifiers

Local EPrints ID: 465497
URI: http://eprints.soton.ac.uk/id/eprint/465497
PURE UUID: cc2d6694-d025-4021-ae79-14801d3012e0

Catalogue record

Date deposited: 05 Jul 2022 01:27
Last modified: 16 Mar 2024 20:13

Export record

Contributors

Author: Neil A Ravenhill

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×