Meeting Abstract
Rapid cold hardening (RCH) is a type of adaptive plasticity in which brief chilling allows insects to significantly enhance their cold tolerance within minutes to hours. RCH is an essential adaptation for dealing with sudden cold snaps and diurnal temperature fluctuations, but the underlying mechanisms are poorly understood. Whereas many stress responses are transcriptionally regulated, the temperatures (around 0°C) and time scales (less than 30 min in some cases) at which RCH occurs are not conducive to the synthesis of new gene products. Rather, protein phosphorylation and other posttranslational signaling events are thought to be the main drivers of RCH, but the identity of these signaling pathways is largely unknown. Here, we used quantitative phosphoproteomics to profile changes in protein phosphorylation that accompany RCH in the flesh fly, Sarcophaga bullata. Brains and fat body were dissected from adult S. bullata, held at either control (25°C) or RCH conditions (2 h at 0°C), then analyzed for global changes in protein phosphorylation using 2D electrophoresis with Pro-Q Diamond staining, which only stains phosphoproteins. Protein spots that exhibited differential phosphorylation were cored and sequenced with LC/MS/MS. RCH caused substantial changes in protein phosphorylation, as we detected 84 proteins that were differentially phosphorylated in the brain and 65 in the fat body. Functional groups that were differentially phosphorylated in both tissue types included heat shock proteins, cytoskeletal genes, and genes involved in metabolism and ATP synthesis. Our results identify a number of candidate signaling events associated with RCH, and future targeted studies will assess the functional significance of these phosphorylation events.
