PtCdc42 is involved in hemocyte mediated immune responses of Portunus trituberculatus under Vibrio parahaemolyticus stimulation.

Rho family small GTPases operate as core molecular switches to modulate vertebrate immune responses, among which cell division cycle 42 (Cdc42) acts as an important member. Although several studies have explored its roles in cellular immunity and pathogen defense in invertebrates, the specific functions and regulatory mechanisms of Cdc42 underlying hemocyte mediated immune responses of Portunus trituberculatus remain to be further elucidated. In the current work, the Cdc42 gene designated PtCdc42 was cloned from P. trituberculatus. Tissue expression profiling demonstrated ubiquitous transcription of PtCdc42 in major immune related tissues, including intestines, hepatopancreas, hemocytes and gill. Treatment with Vibrio parahaemolyticus markedly upregulated PtCdc42 expression. RNAi mediated knockdown of PtCdc42 significantly suppressed the mRNA levels of multiple antimicrobial peptide genes induced by V. parahaemolyticus. Meanwhile, the results indicate that PtCdc42 may participate in hemocyte migration triggered by V. parahaemolyticus and LPS, as well as V. parahaemolyticus stimulated hemocyte phagocytosis.