Abstract 1955 Insulin Signaling Pathways in Corals

Coral reefs cover 0.3% of the ocean and are vital marine ecosystems.Corals live in symbiosis with photosynthetic algae, which provide essential nutrients.Coral bleaching, triggered by environmental stress, is defined by a drastic drop in algae in the coral tissue, often leading to coral death.Between 2009 and 2018, 14% of coral reefs experienced mortality.From 2023 to mid-May 2024, widespread bleaching was documented in over 62 countries, marking the fourth global bleaching event.If current trends continue, 90% of reefs could be at risk by 2030.Understanding the molecular mechanisms behind bleaching is essential for coral resilience.Glucose is a critical metabolite that maintains homeostasis between coral cells and their endosymbionts.Previous coral transcriptome data reveal a glucose regulation systems similar to human energy metabolism.Our studies on Pocillopora damicornis (P.dam) identified 151 GPCR candidates with similarities to human signal transduction pathways.Using remote homology detection, we found insulin (INS), the insulin receptor (INSR), and 67 of 75 human INS signaling proteins likely conserved in P.dam.Based on this finding we hypothesized that INS signaling is present in corals and aberrant signaling, as it occurs in human diabetes, may play a role in coral bleaching.To test this hypothesis, we developed an experimental platform to validate predictions from remote homology modeling.To explore the role of INS signaling in coral physiology, we analyzed downstream protein effects using cell culture, bioinformatics, western blot, and mass spectrometry.Live cells (P.acuta) were dissociated from the coral skeleton using calcium-magnesium-free artificial seawater.Proteins were extracted and analyzed via SDS-PAGE, western blot, and mass spectrometry.Results support the remote homology finding as P.acuta cells stained positive for INSR, phosphorylated and non-phosphorylated ERK1/2 using the respective human antibodies.This research offers new insights into coral molecular mechanisms in resilience, with potential applications in coral pharmacology and conservation.