Meeting Abstract
LEA proteins are a group of hydrophilic polypeptides and have been linked to the survival of plants and animals during prolonged periods of water stress such as freezing and drying. LEA proteins occurring in the brine shrimp (Artemia franciscana) can be classified into 3 different groups (group 1, 3 and 6). The exact function of these proteins is still poorly defined. The aim of our study was to assess the impact of LEA proteins from A. franciscana on both enzyme activity and cellular function under water stress. The group 6 LEA protein AfrSMP, protected activity of the enzyme lactate dehydrogenase (LDH) in bacterial extracts during multiple freeze-thaw cycles, and about 12% higher activity was observed in extracts that contained AfrSMP compared to extracts lacking the protein. Drosophila melanogaster (Kc167) cells that concurrently express two different LEA proteins (AfrLEA3m and AfrSMP; tagged with fluorescence marker proteins), were challenged with NaCl concentrations ranging from 0.1 to 1 M and oxygen consumption was measured. Acute reduction in respiration with increasing salt concentration were similar in control and LEA expressing cells, and extracts of these cells did not exhibit LDH activity above non-transfected control cells when dehydrated. Our result may suggest that the large fluorescent tags hinder the function of LEA proteins. Cells expressing AfrLEA3m-GFP and AfrSMP-mCherry concurrently, showed about 12% higher proliferation rates than control cells when challenged with increasing sucrose concentrations over 48 h. While LEA function may be inhibited by GFP and mCherry, the fluorescent-tagged LEA proteins might still provide some cellular protection during prolonged water stress. Constructs to express untagged LEA proteins are currently being developed. Supported by NSF IOS-1457061/IOS-1456809.
