FIGURE 5.

CatSper-organized quadrilinear nanodomains along the principal piece of the mouse sperm tail A: a confocal image of a CATSPER1-immunostained spermatozoon. Shown is a merged image of fluorescence and the corresponding DIC images. B: a cross-section EM image of immunogold labeled CATSPER1. Shown is a reproduced image from Ref. 6, with permission from Cell. Two clusters of gold particles (red asterisks) are shown at each side of longitudinal columns (LC; pale pink). C: a 3-dimensional 4Pi-single molecule switching nanoscopy (4Pi-SMSN) image of CATSPER1 immunostained wild-type sperm tail. Images are reproduced from Ref. 8, with permission from Cell. shown in x-y (left) and y-z (right) projections. The z-axis information from the focal plane is color coded. Cross-section images from both EM and 4Pi-SMSN hint at a double row of CatSper in each quadrant. Arrowheads in A and C indicate annulus, the junctional part between midpiece and principal piece.