Identification of calmodulin-binding proteins in brain of worker honeybees

Calmodulin is a Ca+ 2-binding protein important in a variety of cell functions. The Ca+ 2/ calmodulin complex interacts with and regulates various enzymes and target proteins, known as calmodulin-binding proteins (CaMBPs). In this study, we revealed a comparative identification of the CaMBPs composition in the worker honeybee (Apis mellifera) brain, considering two different honeybee behaviors in the colony. To this end, the CaMBPs of forager and nurse workers were purified by affinity chromatography, separated in 1D gel, digested and submitted to peptide mass fingerprinting (PMF). In the PMF analysis, 15 different proteins, considered behavior-specific proteins, were identified, one of them exclusively in forager workers and 10 in nurses. All the proteins were classified in terms of their function and cell localization, revealing a greater expression of metabolism-related CaMBPs in both worker subcastes. Protein sequences were then analyzed for the presence of the calmodulin-binding sites. Therefore, the honeybee brain CaMBPs profiles presented differences between worker subcastes. This is the first identification of calmodulin-binding proteins in the brain of A. mellifera upon nursing and foraging behaviors in the colony and this diversity of target proteins for Ca+ 2/CaM may be involved in terms of the function of these proteins in the nervous system.