Sperm protein 17 is expressed in the sperm fibrous sheath

Abstract

Background: Sperm protein 17 (Sp17) is a highly conserved mammalian protein characterized in rabbit, mouse, monkey, baboon, macaque, human testis and spermatozoa. mRNA encoding Sp17 has been detected in a range of murine and human somatic tissues. It was also recognized in two myeloma cell lines and in neoplastic cells from patients with multiple myeloma and ovarian carcinoma. These data all indicate that Sp17 is widely distributed in humans, expressed not only in germinal cells and in a variety of somatic tissues, but also in neoplastic cells of unrelated origin.

Towards the identification of reliable sperm biomarkers for male infertility: A sperm proteomic approach

“…SPA17 is a low molecular weight, mannose‐binding protein that binds to zona pellucida carbohydrates and is therefore an important protein for a number of processes including sperm capacitation, acrosome reaction, recognition and binding to the oocyte zona pellucida, and fertilisation (Chiriva‐Internati et al., ; O'Rand, Widgren, & Fisher, ; Richardson, Yamasaki, & O'Rand, ; Wen, Richardson, & O'Rand, ). In the human testis, a weak expression of this protein was observed in the cytoplasm of spermatocytes, whereas a strong expression was detected in early and late spermatids, which suggests that SPA17 plays a role in the differentiation process.…”

CABYR is essential for fibrous sheath integrity and progressive motility in mouse spermatozoa

“…The Ropn1 Ropn1l double KO mouse line exhibits a complete failure in fertilization (Fiedler et al, 2013). The fourth R2D2-domain-containing protein, SPA17 has not yet been knocked out, although it too can bind to AKAP3 (Lea et al, 2004) and is localized to the fibrous sheath (Chiriva-Internati et al, 2009), indicating that knockout might potentially result in a phenotype similar to that upon loss of CABYR. Combined with our current data on CABYR, it appears that at least three of the four proteins containing the R2D2 domain appear to be essential for the correct formation of a fibrous sheath.…”

The importance of transmission electron microscopy analysis of spermatozoa: Diagnostic applications and basic research

“…The first studies on immunogold staining applied to human sperm mainly concerned the localization of cytoskeletal proteins at the ultrastructural level [Flaherty et al 1988;Kadam et al 2007). Thereafter, other proteins have been detected such as sperm protein 17, a highly conserved mammalian protein in the testis and spermatozoa, distributed throughout the flagellar fibrous sheath [Chiriva-Internati et al 2009].…”