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Ubiquitination precedes internalization and proteolytic cleavage of plasma membrane-bound glycine receptors.

Büttner, C. and Sadtler, S. and Leyendecker, A. and Laube, Bodo and Griffon, N. and Betz, H. and Schmalzing, G. (2001):
Ubiquitination precedes internalization and proteolytic cleavage of plasma membrane-bound glycine receptors.
In: The Journal of biological chemistry, pp. 42978-85, 276, (46), ISSN 0021-9258, [Article]

Abstract

The inhibitory glycine receptor (GlyR) in developing spinal neurones is internalized efficiently upon antagonist inhibition. Here we used surface labeling combined with affinity purification to show that homopentameric alpha1 GlyRs generated in Xenopus oocytes are proteolytically nicked into fragments of 35 and 13 kDa upon prolonged incubation. Nicked GlyRs do not exist at the cell surface, indicating that proteolysis occurs exclusively in the endocytotic pathway. Consistent with this interpretation, elevation of the lysosomal pH, but not the proteasome inhibitor lactacystin, prevents GlyR cleavage. Prior to internalization, alpha1 GlyRs are conjugated extensively with ubiquitin in the plasma membrane. Our results are consistent with ubiquitination regulating the endocytosis and subsequent proteolysis of GlyRs residing in the plasma membrane. Ubiquitin-conjugating enzymes thus may have a crucial role in synaptic plasticity by determining postsynaptic receptor numbers.

Item Type: Article
Erschienen: 2001
Creators: Büttner, C. and Sadtler, S. and Leyendecker, A. and Laube, Bodo and Griffon, N. and Betz, H. and Schmalzing, G.
Title: Ubiquitination precedes internalization and proteolytic cleavage of plasma membrane-bound glycine receptors.
Language: English
Abstract:

The inhibitory glycine receptor (GlyR) in developing spinal neurones is internalized efficiently upon antagonist inhibition. Here we used surface labeling combined with affinity purification to show that homopentameric alpha1 GlyRs generated in Xenopus oocytes are proteolytically nicked into fragments of 35 and 13 kDa upon prolonged incubation. Nicked GlyRs do not exist at the cell surface, indicating that proteolysis occurs exclusively in the endocytotic pathway. Consistent with this interpretation, elevation of the lysosomal pH, but not the proteasome inhibitor lactacystin, prevents GlyR cleavage. Prior to internalization, alpha1 GlyRs are conjugated extensively with ubiquitin in the plasma membrane. Our results are consistent with ubiquitination regulating the endocytosis and subsequent proteolysis of GlyRs residing in the plasma membrane. Ubiquitin-conjugating enzymes thus may have a crucial role in synaptic plasticity by determining postsynaptic receptor numbers.

Journal or Publication Title: The Journal of biological chemistry
Volume: 276
Number: 46
Divisions: 10 Department of Biology
10 Department of Biology > Neurophysiology and Neurosensory Systems
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Date Deposited: 11 Apr 2011 13:27
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