Regulation of tail muscle arginine kinase by reversible phosphorylation in an anoxia-tolerant crayfish

Dawson, N. J. and Storey, K. B. (2011) Regulation of tail muscle arginine kinase by reversible phosphorylation in an anoxia-tolerant crayfish. Journal of Comparative Physiology B: Biochemical, Systems, and Environmental Physiology, 181(7), pp. 851-859. (doi: 10.1007/s00360-011-0578-y) (PMID:21519878)

Full text not currently available from Enlighten.

Abstract

Freshwater crayfish, Orconectes virilis, can experience periodic exposures to hypoxia or anoxia due to low water flow (in summer) or ice cover (in winter) in their natural habitat. Hypoxia/anoxia disrupts energy metabolism and triggers mechanisms that to support ATP levels while often also suppressing ATP use. Arginine kinase (AK) (E.C. 2.7.3.3) is a crucial enzyme involved in energy metabolism in muscle, gating the use of phosphagen stores to buffer ATP levels. The present study investigated AK from tail muscle of O. virilis identifying changes to kinetic properties, phosphorylation state and structural stability between the enzyme from aerobic control and 20 h anoxic crayfish. Muscle AK from anoxia-exposed crayfish showed a significantly higher (by 59%) K m for L-arginine and a lower I50 value for urea than the aerobic form. Several lines of evidence indicated that AK was converted to a high phosphate form under anoxia: (a) aerobic and anoxic forms of AK showed well-separated elution peaks on DEAE ion exchange chromatography, (b) ProQ Diamond phosphoprotein staining showed a 64% higher bound phosphate content on anoxic AK compared with the aerobic form, and (c) treatment of anoxic AK with alkaline phosphatase reduced K m L-arginine to aerobic levels whereas incubation of aerobic AK with protein kinase A catalytic subunit raised the K m to anoxic levels. The physiological consequence of anoxia-induced AK phosphorylation may be to suppress AK activity in the phosphagen-synthesizing direction and, together with reduced cellular pH and ATP levels, promote the phosphagen-catabolizing direction under anoxic conditions. This is first time that AK has been shown to be regulated by reversible phosphorylation.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Dawson, Dr Neal
Authors: Dawson, N. J., and Storey, K. B.
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Journal of Comparative Physiology B: Biochemical, Systems, and Environmental Physiology
Publisher:Springer
ISSN:0174-1578
ISSN (Online):1432-136X
Published Online:26 April 2011

University Staff: Request a correction | Enlighten Editors: Update this record