Identification of the Molecular Chaperone, Heat Shock Protein 1 (Chaperonin 10), in the Reproductive Tract and in Capacitating Spermatozoa in the Male Mouse1

Abstract

Mammalian spermatozoa must undergo epididymal maturation in the male reproductive tract and capacitation in the female tract before acquiring the ability to fertilize an oocyte. Previous studies from our laboratory have demonstrated a causal relationship between capacitation-associated surface phosphotyrosine expression and the ability of mouse spermatozoa to recognize the oocyte and engage in sperm-zona pellucida interaction. Our previous analyses of the surface phosphoproteome of capacitated murine spermatozoa identified two molecular chaperones, heat shock protein (HSP) D1 and HSP90B1, with well-characterized roles in protein folding and the assemblage of multimeric protein complexes. The expression of these chaperones was restricted to the rostral aspect of the sperm head, in an ideal position to mediate sperm-zona pellucida interaction. Herein, we report the characterization of an additional chaperone in this location, HSPE1 (chaperonin 10; HSP10). This chaperone was identified using a coimmunoprecipitation strategy employing HSPD1 as bait. The putative interaction between HSPE1 and HSPD1 was supported by reciprocal immunoprecipitation and colocalization studies, which demonstrated the coordinated appearance of both proteins on the surface of the sperm head during capacitation. However, the surface exposure of the protein was lost upon induction of acrosomal exocytosis, as would be expected of a protein potentially involved in sperm-zona pellucida interaction. Collectively, these data invite speculation that a number of molecular chaperones are involved in modification of the sperm surface during capacitation to render these cells functionally competent to engage the process of fertilization.

Expressions of miR-15a and its target gene HSPA1B in the spermatozoa of patients with varicocele

“…Specifically, HSPs are critically important during spermatogenesis and the posttesticular maturation of mammalian spermatozoa that aberrant expression is associated with spermatogenesis arrested and defects in sperm function (Dun et al 2012). The stage-specific expression pattern displayed by HSPs during spermatogenesis indicates that HSPs are involved in germ cell development (Feng et al 2001, Huo et al 2004, Asquith et al 2005, Terada et al 2005, Held et al 2006, Adly et al 2008, Walsh et al 2008, Lachance et al 2010, Ji et al 2012. In addition, HSPA1B has been implicated in fertilization and embryo development (Neuer et al 2000, Matwee et al 2001.…”

Whole-body heat exposure induces membrane changes in spermatozoa from the cauda epididymidis of laboratory mice

“…One cauda epididymidis was removed from each animal from control and heat-treated groups, then blotted on filter paper and placed in equal volume of 500 µL prewarmed modified Biggers, Whitten and Whittingham (BWW) medium [19]. Spermatozoa were extruded by retrograde perfusion of BWW into the vas deferens after making a small incision in the cauda epididymidis [20]. They were allowed to disperse into the medium in an incubator, maintained at 37ºC with 5% CO2 in air, for 10 min.…”

Unfolding the relationship between secreted molecular chaperones and macrophage activation states

“…This turned out to be the molecular chaperone, chaperonin (Cpn)/heat shock protein (Hsp)10, a mitochondrial protein (Cavanagh and Morton 1994). Co-incidentally, both Hsp10 and the co-chaperone Hsp60 are now implicated as cell surface proteins essential for the capacitation of sperm, revealing a 'prior role' for these proteins in pregnancy (Walsh et al 2008). However, it was Hightower, 1 year after the description of the mechanism of action of Hsp60, who first revealed that a molecular chaperone, in this case Hsp70, was released by cells (Hightower and Guidon 1989).…”