Molecular heterogeneity of gelatin-binding proteins from human seminal plasma

Abstract

Defining the molecular characteristics of seminal plasma proteins is essential for understanding their function in physiological and pathological conditions. Starting from the predicted importance of human seminal plasma gelatin-binding proteins, comprising fibronectin (FN) and FN-related molecules, for male fertility, this study aims at gaining insight into their immuno-glycobiochemical properties. Human seminal plasma from subjects with normal semen parameters were separated on a gelatin-Sepharose column and analyzed by sodium dodecyl sulfatepolyacrylamide gel electrophoresis and immunoblotting using antibodies against distinct FN forms. Heterogeneity of the isolated molecular species was examined by protein chip arrays combined with surface-enhanced laser desorption/ionization time of flight mass spectrometry, on normal, metal and hydrophobic surfaces. Carbohydrate composition was investigated using mannose-, fucose-and sialic acid-specific plant lectins and galectin-1. The results obtained indicated a pattern of isolated proteins corresponding to that of known FN fragments, as confirmed by immunoreactivity. Among them heparin-binding ability was preferentially associated with low molecular mass species. As for posttranslational modifications, phosphorylation and glycosylation of distinct fragments were revealed. Lectin binding to fragments containing the gelatin-binding domain, particularly with Ricinus communis agglutinin I, was stronger than to fragments containing the cell-binding site of FN. A low level of sialylation and distinctive concanavalin A-and Lens culinaris agglutinin-reactive species were also observed. Galectin-1 did not interact with the isolated preparation. Resolving the molecular heterogeneity of normal human seminal plasma FN and gaining initial insight into possible similarities/differences with known FN molecular species may be considered a prerequisite step preceding challenging the clinical usefulness of these molecular properties.

Bovine seminal PDC-109 protein: An overview of biochemical and functional properties

“…Group of HBPs (14)(15)(16)(17)(18) are the same as BSP proteins (Therien et al, 1995). 1 Cattle BSP-A1/-A2 (PDC-109), BSP-A3, BSP-30-kDa Esch et al (1983) 2 Rat, Hamster BSP-like antigens Leblond et al (1993) 3 Stallion HSP-1, -2, -12-kDa Calvete et al (1995a) 4 Swine pB-1 Calvete et al (1997) 5 Goat GSP-14, -15, -20, -22-kDa Villemoure et al (2003) 6 Sheep BSP-like antigen Bergeron et al (2005) 7 Buffalo BSP-like antigen Arangasamy et al (2005) 8 Human BSP-like antigen Kosanović and Jankovi (2010) …”

Etiology of Antisperm Antibodies in the Serum of Virgins

“…Sperm is considered as a highly diverse antigenic cell, it contains antigens that can be modified during processes of maturation and ejaculation, e.g. the binding of soluble fibronectin to the tail of sperm [2]. During the early years of the 20th century, researchers had shown that spermatozoal and seminal plasma antigenic components can stimulate both specific autoimmunity and isoimmunity.…”

Fucose and Sialic Acid Expressions in Human Seminal Fibronectin andα1-Acid Glycoprotein Associated with Leukocytospermia of Infertile Men

“…The reactivities of normal seminal plasma fibronectin with fucose-specific AAL and UEA, and sialo-specific MAA and SNA suggest that FN is heavily fucosylated through the α1,6and α1,2-types of linkages, but weakly by α1,3-linked fucose, and is poorly sialylated ( Table 1). The presence of fucose α1,6-linked in seminal fibronectin has been proved by Kosanović and Janković [17]. Human blood plasma α 1 -acid glycoprotein does not contain α1,6and α1,2linked fucoses, but contains variable amount of fucose α1,3-linked, and is heavily sialylated, mainly through α2,6-type of linkage [18,34,37].…”

“…Seminal plasma totally lacks the intact fibronectin form and consists of FN fragments derived from those FN domains which are known to be glycosylated, i.e. the cell-binding domain [15,35] and collagendomain [17]. Distribution of hypo-and a-sialylated FN glycoforms has been found to be associated with abnormal semen parameters and with high concentrations of fibronectin [14].…”