Meeting Abstract
Late Embryogenesis Abundant (LEA) proteins are a class of highly hydrophilic intrinsically disordered polypeptides (IDP) that are found in many plants and some anhydrobiotic animals. Over 15 distinct LEA proteins, belonging to three different classification groups (1,3 and 6), have been found in Artemia franciscana and several of these proteins have been shown to be involved in the anhydrobiotic life history stage of these Branchiopods. The exact mechanisms by which specific LEA proteins protect brine shrimp embryos during desiccation is largely unknown. To gain understanding into the possible mechanisms of protection conferred by group 1 and 6 LEA proteins, enzyme assays were utilized to investigate the effect of AfLEA1.1 and AfrLEA6 on lactate dehydrogenase (LDH) activity in lysate of Drosophila melanogaster Kc167 cells after desiccation and rehydration. Cell lysates were utilized to probe for specific interactions between LDH and LEA proteins during water-stress in a proteome system. This may closer resemble potential interaction in the cytoplasm than observed in a binary protein study with purified enzymes and a specific LEA protein. Results show that AfLEA1.1 added to purified LDH protected the enzyme during desiccation and rehydration, however, when added to cell lysate, no protection of enzymatic activity was observed after rehydration compared to LEA-free control lysates. Similarly, no protection of LDH activity by AfrLEA6 was observed when the protein was added to cell lysates before desiccation compared to LEA-free controls. It appears likely that the protection of enzymatic activity observed by AfLEA1.1 in the binary protein system might be an overestimate and LDH is not a specific target of AfLEA1.1 under physiological conditions (supported by NSF IOS-1659970).
