Although calnexin is essential in i S pombe its highly conserved central domain is dispensable for viability

Elagöz, Aram, Callejo, Mario, Armstrong, John and Rokeach, Luis A (1999) Although calnexin is essential in i S pombe its highly conserved central domain is dispensable for viability. Journal of Cell Science, 112 (23). 4449 - 4460. ISSN 00219533

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Abstract

In mammalian cells, the calnexin/calreticulin chaperones play a key role in glycoprotein folding and its control within the endoplasmic reticulum (ER), by interacting with folding intermediates via their monoglucosylated glycans. This lectin activity has been mapped in mammalian calnexin/calreticulin chaperones to the central region, which is a highly conserved feature of calnexin/calreticulin molecules across species. The central domain has also been implicated in Ca2+ binding, and it has been proposed to be involved in the regulation of calcium homeostasis in the ER. Herein, we show that although the Schizosaccharomyces pombe calnexin is essential for viability, cells lacking its 317-amino-acid highly conserved central region are viable under normal growth conditions. However, the central region appears to be necessary for optimal growth under high ER-stress, suggesting that this region is important under extreme folding situations (such as DTT and temperature). The minimal length of calnexin required for viability spans the C-terminal 123 residues. Furthermore, cells with the central domain of the protein deleted were affected in their morphology at 37°C, probably due to a defect in cell wall synthesis, although these mutant cells exhibited the same calcium tolerance as wild-type cells at 30°C.

Item Type: Article
Schools and Departments: School of Life Sciences > Biochemistry
Depositing User: John Armstrong
Date Deposited: 06 Feb 2012 19:08
Last Modified: 20 Mar 2012 13:48
URI: http://sro.sussex.ac.uk/id/eprint/19375
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