title: Vitamin K-dependent protein S in Leydig cells of human testis.
abstract: Protein S is an anticoagulant plasma protein, functioning as a cofactor to activated protein C in the regulation of blood coagulation. In addition, protein S forms a complex with the complement regulatory protein, C4b-binding protein. Protein S is unique among the vitamin K-dependent proteins in being structurally similar to androgen binding proteins. Protein S immunoreactivity was demonstrated in Leydig cells of human testis. In Northern blotting experiments, the presence of protein S mRNA in human testis tissue could be shown. In situ hybridization experiments localized protein S mRNA to the Leydig cells, demonstrating transcription of the protein S gene in these cells. Five protein S clones were isolated from a human testis cDNA library, partially sequenced and characterized by restriction enzyme mapping. Three unique clones contained information for the entire coding sequence and approximately two-thirds of the 5' and 3' non-coding sequences. The results indicate the nucleotide sequences of testis and liver protein S mRNA to be identical. No binding of androgens to protein S could be demonstrated. In conclusion, we demonstrate the presence of protein S immunoreactivity as well as protein S mRNA in the Leydig cells of human testis. These results suggest local synthesis of protein S in Leydig cells of human testis which may be functionally important for local anticoagulation.
authors.affiliation: Department of Clinical Chemistry, University of Lund, Malmö General Hospital, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Malm
authors.forename: X H
authors.initials: XH
authors.lastname: He
authors.forename: A
authors.initials: A
authors.lastname: Bjartell
authors.forename: L
authors.initials: L
authors.lastname: Shen
authors.forename: P A
authors.initials: PA
authors.lastname: Abrahamsson
authors.forename: B
authors.initials: B
authors.lastname: Dahlbäck
mesh_terms: D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007985:Leydig Cells / Q000737:chemistry* / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes; D017293:Protein S / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D015345:Oligonucleotide Probes; D017293:Protein S; D012333:RNA, Messenger