Regulation of pyruvate kinase and glycerol-3-phosphate dehydrogenase in the freeze tolerant goldenrod gall fly: role in polyol cryoprotectant production

Larvae of the goldenrod gall fly, Eurosta solidaginis, can survive winter temperatures as cold as –55oC by using the freeze tolerance strategy of cold hardiness. This study examines pyruvate kinase (PK) and glycerol-3-phosphate dehydrogenase (G3PDH) that were purified from gall fly larvae acclimated to 5oC (control) and −15oC (freeze-exposed). The roles that these enzymes play in polyol cryoprotectant synthesis and metabolic regulation were investigated. A primary focus was the potential for reversible post-translational modifications (PTMs) to regulate enzyme activity. Several PTMs were analyzed for PK and G3PDH from control and freeze-exposed gall fly larvae using dot-blot analysis. Results showed that low and high phosphate forms of each enzyme exist and these differ in kinetic properties, G3PDH also showed different levels of ubiquitination. Changes in substrate affinities and different interactions with endogenous sugars suggest that PK activity is maintained whereas G3PDH is inhibited during freezing.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Master's

Discipline thesis:degree_discipline

Biology

Grantor dc:publisher

Carleton University

Year dc:date.issued

2015

Author dc:creator

• Abboud, Jean

Statement dc:rights

• Copyright © 2015 the author(s). Theses may be used for non-commercial research, educational, or related academic purposes only. Such uses include personal study, research, scholarship, and teaching. Theses may only be shared by linking to Carleton University Institutional Repository and no part may be used without proper attribution to the author. No part may be used for commercial purposes directly or indirectly via a for-profit platform; no adaptation or derivative works are permitted without consent from the copyright owner.

Language dc:language.iso

en

DOI

10.22215/etd/2015-10963

OAI identifier oai:identifier

oai:carleton.scholaris.ca:20.500.14718/32638