Calcineurin differentially functions in innate immune response of Caenorhabditis elegans fed with gram-positive or gram-negative bacteria

Abstract

Innate immunity in Caenorhabditis elegans involves multiple processes including growth factor pathways, neuroendocrine signaling mediating various kinase activities. In this study, we report that calcineurin, a Ca2+/calmodulin-dependent serine/threonine phosphatase, regulates the nematode's vulnerability to bacterial pathogens. Interestingly, calcineurin seems to differently function in host-pathogen interaction of gram-positive and gram-negative bacteria. In addition, loss of calnexin, a Ca2+-binding chaperone in endoplasmic reticulum, compensates immune response of the nematode to gram-negative bacteria, while that of calreticulin has no effect. The results suggest that C. elegans has evolved different immune response strategy to gram-positive or gram-negative bacteria, utilizing the same immune machinery in different modes.