Single cell imaging reveals that the motility regulator speract induces a flagellar alkalinization that precedes and is independent of Ca²⁺ influx in sea urchin spermatozoa.
Speract, a peptide from the egg jelly coat of certain sea urchin species, modulates sperm motility through a signaling pathway involving several ionic fluxes leading to pHi and [Ca²⁺]i increases. [Ca²⁺]i oscillations in the flagellum regulate its beating pattern modulating sperm swimming. Recent evidence showed the importance of pHi in controlling Ca²⁺ influx and chemotaxis. However, spatio-temporal characterization of the flagellar pHi increase triggered by speract, and its correlation to that of [Ca²⁺]i is lacking. Here, we show for the first time in single sea urchin spermatozoa that the speract-induced flagellar pHi increase precedes and is independent of [Ca²⁺]i increase. Our results support a leading role of pHi in modulating the Ca²⁺ signals that govern sperm swimming.
['González-Cota|Ana Laura|AL|', 'Silva|Pedro Ângelo|PÂ|', 'Carneiro|Jorge|J|', 'Darszon|Alberto|A|']
D000468:Alkalies D000643:Ammonium Chloride D000818:Animals D020013:Calcium Signaling D003593:Cytoplasm D006863:Hydrogen-Ion Concentration D007091:Image Processing, Computer-Assisted D007700:Kinetics D008297:Male D009842:Oligopeptides D012617:Sea Urchins D059010:Single-Cell Analysis D013077:Sperm Head D013081:Sperm Motility D013082:Sperm Tail D013094:Spermatozoa
Motility regulation Speract Sea urchin Sperm Intracellular pH and Ca(2+)