JAM-A is present in mammalian spermatozoa where it is essential for normal motility.
Junctional adhesion molecules (JAMs) that are expressed in endothelial and epithelial cells and function in tight junction assembly, also perform important roles in testis where the closely-related JAM-A, JAM-B, and JAM-C are found. Disruption of murine Jam-B and Jam-C has varying effects on sperm development and function; however, deletion of Jam-A has not yet been studied. Here we show for the first time that in addition to expression in the Sertoli-Sertoli tight junctions in the seminiferous tubules, the approximately 32 kDa murine JAM-A is present in elongated spermatids and in the plasma membrane of the head and flagellum of sperm. Deletion of Jam-A, using the gene trap technology, results in flagellar defects at the ultrastructural level. In Jam-A-deficient mice, which have reduced litter size, both progressive and hyperactive motility are significantly affected (P<0.0001) before and, more severely, after capacitation. The findings show that JAM-A is involved in sperm tail formation and is essential for normal motility, which may occur via its signal transduction and protein phosphorylation properties. Detection of JAM-A in human sperm proteins indicates that its role may be conserved in sperm motility and that JAM-A may be a candidate gene for the analysis of idiopathic sperm motility defects resulting in male subfertility in the human population.
Shao
Minghai
M
Department of Biological Sciences, 219 McKinly Lab, University of Delaware, Newark, DE 19716, USA.
Ghosh
Ananya
A
Cooke
Vesselina G
VG
Naik
Ulhas P
UP
Martin-DeLeon
Patricia A
PA
D000818:Animals; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000502:physiology*; D004822:Epididymis / Q000502:physiology; D006801:Humans; D007136:Immunoglobulins / Q000032:analysis / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011956:Receptors, Cell Surface / Q000032:analysis / Q000502:physiology*; D013081:Sperm Motility; D013094:Spermatozoa / Q000737:chemistry*
D015815:Cell Adhesion Molecules; C407243:F11R protein, human; C498686:F11r protein, mouse; D007136:Immunoglobulins; D011956:Receptors, Cell Surface