title: 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.
abstract: 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.
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Col. Chamilpa, C.P. 62210 Cuernavaca, Mor., México.
authors.forename: Ana Laura
authors.initials: AL
authors.lastname: González-Cota
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, Portugal.
authors.forename: Pedro Ângelo
authors.initials: PÂ
authors.lastname: Silva
authors.affiliation: Instituto Gulbenkian de Ciência, Oeiras, Portugal.
authors.forename: Jorge
authors.initials: J
authors.lastname: Carneiro
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Avenida Universidad 2001, Col. Chamilpa, C.P. 62210 Cuernavaca, Mor., México. Electronic address: darszon@ibt.unam.mx.
authors.forename: Alberto
authors.initials: A
authors.lastname: Darszon
mesh_terms: D000468:Alkalies / Q000494:pharmacology; D000643:Ammonium Chloride / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D008297:Male; D009842:Oligopeptides / Q000378:metabolism*; D012617:Sea Urchins / Q000502:physiology*; D059010:Single-Cell Analysis; D013077:Sperm Head / Q000378:metabolism; D013081:Sperm Motility / Q000187:drug effects; D013082:Sperm Tail / Q000187:drug effects / Q000378:metabolism*; D013094:Spermatozoa / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism
chemical_list: D000468:Alkalies; D009842:Oligopeptides; D000643:Ammonium Chloride; C028364:speract
keywords: Intracellular pH and Ca(2+); Motility regulation; Sea urchin; Speract; Sperm