Flagellasialin: a novel sulfated alpha2,9-linked polysialic acid glycoprotein of sea urchin sperm flagella.
A novel alpha2,9-linked polysialic acid (polySia)-containing glycoprotein of sea urchin sperm flagella was identified and named "flagellasialin." Flagellasialin from Hemicentrotus pulcherrimus shows a diverse relative molecular mass on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of 40-80 kDa. Flagellasialin is a 96-amino acid, threonine-rich, heavily O-glycosylated (80-90% by weight) glycoprotein with a single transmembrane segment at its C-terminus and no apparent cytosolic domain. Of 12 extracellular Thr residues, eight are O-glycosylated and three are nonglycosylated. Flagellasialin is highly expressed in the testis but cannot be detected in the ovary. The amino acid sequences of flagellasialin from three sea urchin species (H. pulcherrimus, Strongylocentrotus purpuratus, and Strongylocentrotus franciscanus) are identical, but some species differences exist in the three core glycan structures to which the sulfated alpha2,9-linked polyNeu5Ac chain is linked. Finally, the treatment of sperm with a specific antibody against the alpha2,9-linked polyNeu5Ac structure results in the elevation of intracellular Ca(2+) and inhibition of sperm motility and fertilization, implicating flagellasialin as a regulator of these critical processes.
Miyata
Shinji
S
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan.
Sato
Chihiro
C
Kumita
Hironobu
H
Toriyama
Masaru
M
Vacquier
Victor D
VD
Kitajima
Ken
K
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D005306:Fertilization / Q000187:drug effects / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D006031:Glycosylation; D008297:Male; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000276:immunology; D010053:Ovary / Q000378:metabolism; D011134:Polysaccharides / Q000032:analysis; D012617:Sea Urchins / Q000378:metabolism*; D012794:Sialic Acids / Q000032:analysis*; D013081:Sperm Motility / Q000187:drug effects / Q000235:genetics; D013082:Sperm Tail / Q000378:metabolism*; D013094:Spermatozoa / Q000187:drug effects / Q000378:metabolism; D013431:Sulfates / Q000032:analysis; D013737:Testis / Q000378:metabolism
D000906:Antibodies; D018076:DNA, Complementary; D006023:Glycoproteins; D011134:Polysaccharides; D012794:Sialic Acids; D013431:Sulfates; C021319:polysialic acid; D019158:N-Acetylneuraminic Acid