The regulatory role of arginine kinase during larval settlement of the bryozoan Bugula neritina

Larval attachment and metamorphosis, also collectively known as settlement, plays an important role in the life history of marine invertebrates with biphasic life cycle. Bugula neritina can settle on any substrate without substrate selection. This complex transformation usually involves an active selection process, while the larval decision to settle is regulated by both exogenous and endogenous factors. This study focuses on the involvement of arginine kinase (AK), an important enzyme that regulates energy metabolism in marine invertebrates, during larval settlement of the bryozoan Bugula neritina. We reveal that AK was highly expressed in the swimming larvae of B. neritina, while its expression was down-regulated post-attachment. When treated with AK inhibitors, the larval settlement rate was significantly decreased. In addition, the immunostaining results indicated that AK was mainly localized to the neuro-muscular cord in swimming larvae. Overall, our results suggest the involvement of AK in regulating larval settlement of B. neritina.