Fig 12. Proposed scheme of Ca²⁺ signaling pathways leading to regulation of AMPK activity in avian sperm.

This schematic diagram shows potential mechanisms of calcium role through CaMKK stimulation in chicken sperm. They all activate AMPK and CaMKI, which leads to metabolic improvements, leading themselves to the control of sperm functions. Solid arrows and blocked arrows illustrate more established relationships between stimuli, signals, improved metabolic status and control of avian sperm functions. Solid black arrows indicate Ca²⁺/CaMKKs/AMPK signaling pathway. Dashed black arrows indicate Ca²⁺/CaM/CaMKKs/CaMKI signaling pathway. Curved arrows (black) indicate AMPK phosphorylation, CaMKI phosphorylation; dashed grey arrows with a question mark are used for hypotheses.