Meeting Abstract

P1.46  Jan. 4  Integrin regulation of budding in Hydra BEASLEY, S.D.*; SAWYER, S. J; Southern Illinois University; Southern Illinois University sasawye@siue.edu

Cnidarians were the first animals to evolve a true epithelial tissue; however little is understood about epithelial regulation in these animals. Tissue integrity is controlled by both cell-cell adhesion, mediated by cadherins, and cell-substrate adhesion, mediated by integrins. To better understand the role of integrins in controlling tissue integrity in Cnidarians, we are investigating the function of integrins during budding in Hydra, a process that must involve cell rearrangements and therefore integrins. We initially investigated how protein phosphorylation of integrins affected budding using the protein phosphatase inhibitors PP2 and okadaic acid. The src kinase inhibitor, PP2 at 500nM inhibited bud formation in Hydra. We are also investigating serine/threonine phosphorylation inhibitors. The beta subunit of integrins when phosphorylated on serine/threonine residues cannot interact with the actin cytoskeleton and therefore, cannot initiate cell migration. Okadaic acid prevents dephosphorylation of serine/threonine residues. Our experiments have shown that both 20nM and 25nM okadaic acid treatments prevent bud formation Our next set of experiments is using immunohistochemistry to look at how these agents affect the distribution of integrins with the buds. These experiments will yield insight into how integrin signaling is regulated in these animals. Our results suggest that the proper phosphorylation status of integrins as well as integrin signaling is needed to get bud formation in Hydra. This suggests that integrin signaling in Hydra is similar to that found in higher metazoans.