Channels that line the tail of sperm contain pores that allow the entry of calcium, which fuels their journey to the female reproductive tract.
In a new study, researchers from Yale and the University of Texas Southwestern captured images of critical components of these so-called CatSper ion channels, revealing that they are interconnected and arranged in zig-zag fashion. This molecular architecture allows for the highly coordinated whip-like action of the sperm tail that propels it to its goal, they report in the journal Nature Communications.
"The subunits of these channels are arranged like staggered beads on a necklace in a double row," said Jean-Ju Chung, associate professor of cellular and molecular physiology at Yale and co-corresponding author of the research.
Chung and her Yale colleagues had previously identified the CatSper channel complex, which is linearly arranged along the flagella of sperm, as the primary driver of sperm's hyperactivated motility. The use of cryo-electron tomography allowed researchers in the new study to view the channel complex at the atomic level, revealing an important glimpse of the complex relationship of components along the channels which are essential to jumpstarting life in mammals.
Daniel Nicastro of UT Southwestern is co-corresponding author. The collaboration also included the research groups of Polina Lishko and Karen Davies at the University of California-Berkeley and Gunther Wennemuth of the University of Duisburg-Essen. Yale's Huafeng Wang and Yanhe Zhao of UT Southwestern are co-lead authors.
