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AMP‐activated protein kinase (AMPK) affects temperature tolerance in the rock crab, Cancer irroratus
Author(s) -
O'Rourke Michaela,
Bucicchia Christina,
Furey Nathan,
Frederich Markus
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a592-a
Subject(s) - ampk , protein kinase a , activator (genetics) , chemistry , amp activated protein kinase , medicine , endocrinology , metformin , hsp70 , phosphorylation , biology , biochemistry , heat shock protein , insulin , receptor , gene
Exposure of marine invertebrates to high temperatures leads to a switch from aerobic to anaerobic metabolism, a drop in cellular [ATP], and subsequent death. In mammals AMP‐activated protein kinase (AMPK) is a major regulator of cellular [ATP] that activates ATP‐producing pathways while inhibiting ATP‐consuming pathways. We hypothesized that temperature stress activates AMPK to provide adequate [ATP] at higher sublethal temperatures. Cancer irroratus, were exposed to a progressive temperature increase (6°C/h) from 12 to 30°C and heart rate was recorded. Western blots measured AMPK activity, total AMPK protein and HSP70 levels of hearts taken at 2°C increments. In a separate experiment the AMPK activator Metformin was injected prior to temperature stress. AMPK activity remained constant between 12 and 18°C and increased linearly 9.1±1.5 fold between 18 and 30°C (ANOVA, p<0.05). HSP70 and total AMPK levels showed no changes. Metformin increased AMPK activity 2.8±0.8 fold (p<0.05) at 12°C. Metformin reduced maximum heart rates compared to saline injected controls (113±19 vs. 153±60 bpm, p<0.05) and these crabs were less temperature tolerant (maximum bpm at 23 vs. 29°C). We conclude that AMPK is an early indicator of temperature stress. AMPK activity increases with temperature, but enhanced AMPK activity reduces temperature tolerance. Therefore, AMPK plays an important role in temperature tolerance in crabs.