Network model predicts that CatSper is the main Ca2+ channel in the regulation of sea urchin sperm motility

• Published in: Scientific reports Vol. 7; no. 1; pp. 1 - 14
• Main Authors: Espinal-Enríquez, Jesús, Priego-Espinosa, Daniel Alejandro, Darszon, Alberto, Beltrán, Carmen, Martínez-Mekler, Gustavo
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 26-06-2017; Nature Publishing Group; Nature Portfolio
• Subjects: 631/553/2710; 631/553/2711; 82/58; Calcium (intracellular); Calcium channels; Calcium signalling; Chemotaxis; Flagella; Humanities and Social Sciences; Intracellular signalling; Invertebrates; multidisciplinary; Peptides; Science; Science (multidisciplinary); Signal transduction; Sperm; Swimming; Swimming behavior
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-017-03857-9

Spermatozoa sea urchin swimming behaviour is regulated by small peptides from the egg outer envelope. Speract, such a peptide, after binding to its receptor in
Strongylocentrotus purpuratus
sperm flagella, triggers a signaling pathway that culminates with a train of intracellular calcium oscillations, correlated with changes in sperm swimming pattern. This pathway has been widely studied but not fully characterized. Recent work on
Arbacia punctulata
sea urchin spermatozoa has documented the presence of the Ca
2+
CatSper channel in their flagella and its involvement in chemotaxis. However, if other calcium channels participate in chemotaxis remains unclear. Here, based on an experimentally-backed logical network model, we conclude that CatSper is fundamental in the
S. purpuratus
speract-activated sea urchin sperm signaling cascade, although other Ca
2+
channels could still be relevant. We also present for the first time experimental corroboration of its active presence in
S. purpuratus
sperm flagella. We argue, prompted by
in silico
knock-out calculations, that CatSper is the main generator of calcium oscillations in the signaling pathway and that other calcium channels, if present, have a complementary role. The approach adopted here allows us to unveil processes, which are hard to detect exclusively by experimental procedures.