Plasminogen activatior inhibitor type 1 in rat spermatozoa: localisation in the tail, in the acrosome and on the surface of the head

Abstract

Isolated seminiferous tubules of rat testis contain considerable urokinase-inhibiting activity. An immunohistological analysis revealed the presence of plasminogen activator inhibitor type 1 (PAI-1) in the basement membrane as well as in the interior of the tubules. Distribution and intensity of the intratubular immunoreactivity depends on the stage of the seminiferous cycle. A relatively weak signal is present around elongated nuclei of spermatids at the beginning of chromatin condensation. The signal intensity increases in the course of differentiation until a maximum is reached at stages VII-VIII. In these stages PAI-1 immunoreactivity is localised around the nuclei of the late spermatids as well as along their tails. Spermatozoa in the ductus epididymis also strongly react with the PAI-1-specific antiserum, suggesting that the inhibitor remains associated with the germ cells after spermiation and during maturation in the epididymis. In intact mature spermatozoa isolated from epididymis cauda by 'swimming-up' in non-capacitation medium, PAI-1 antigen is localised on the plasma membrane surrounding the head. In addition, in fixed and permeabilised cells the immunoreactivity is detectable in the acrosome and in the tail. Possible functions of PAI-1 in spermatogenesis, sperm motility and sperm-egg interaction are discussed.

Involvement of Plasminogen Activator and Plasminogen Activator Inhibitor Type 1 in Spermatogenesis, Sperm Capacitation, and Fertilization

“…19 Mouse spermatozoa have the surface-bound u-PA, 20 which appear to be acquired for the modifications from the genital tract secretions at ejaculation acrosomal reaction. [30][31][32][33][34] Zheng et al 30 and Zhang et al 35 have performed a serious of experiments to show that t-PA, u-PA, and PAI-1 were expressed in the epididymis (Fig. 5), seminal Figure 3 Regulation of tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen (u-PA) activity in cultured (A) rat and (B) mouse seminiferous tubule segments at stages II to VI, VII to VIII, and IX to XII.…”

Non-Steroidal Signal Molecules in Spermatogenesis

“…In mature caudal sperm, PAI-I is localized on the plasma membrane surrounding the head. In addition the activity was detectable in the acrosome and in the tail (Manske et al, 1994). It appeared that there exists a direct linkage between molecular events triggered by phagocytosis and the regulation of tPA and PAI-1 in Sertoli cells (Bourdon et al, 1999).…”

The Family Secrets of Avian Egg-Specific Ovalbumin and Its Related Proteins Y and X

“…Indeed, Protein C inhibitor/SERPINA5, a serpin inhibiting trypsin-like proteases has been suggested to protect human spermatozoa against premature acrosome reaction and degradation, thereby modulating the acrosin activity so that it can coincide with binding to the oocyte [58]. Similarly, Plasminogen Activator Inhibitor 1/SERPINB2) has been shown to bind mammalian spermatozoa [59] and has been proposed to preserve the oocyte/embryo from degradation and/or extracellular matrix remodeling of both oviduct and early cleavage-stage embryo [60] Considering OVAX, it was shown to exhibit antimicrobial activities against at least two pathogens, Listeria monocytogenes and Salmonella enterica Enteritidis via its heparin-binding domain (positively charged domain) [12] (Figure 3). These activities suggest a role for OVAX at least in egg defense.…”