title: SEPT12 phosphorylation results in loss of the septin ring/sperm annulus, defective sperm motility and poor male fertility.
abstract: Septins are critical for numerous cellular processes through the formation of heteromeric filaments and rings indicating the importance of structural regulators in septin assembly. Several posttranslational modifications (PTMs) mediate the dynamics of septin filaments in yeast. However, little is known about the role of PTMs in regulating mammalian septin assembly, and the in vivo significance of PTMs on mammalian septin assembly and function remains unknown. Here, we showed that SEPT12 was phosphorylated on Ser198 using mass spectrometry, and we generated SEPT12 phosphomimetic knock-in (KI) mice to study its biological significance. The homozygous KI mice displayed poor male fertility due to deformed sperm with defective motility and loss of annulus, a septin-based ring structure. Immunohistochemistry of KI testicular sections suggested that SEPT12 phosphorylation inhibits septin ring assembly during annulus biogenesis. We also observed that SEPT12 was phosphorylated via PKA, and its phosphorylation interfered with SEPT12 polymerization into complexes and filaments. Collectively, our data indicate that SEPT12 phosphorylation inhibits SEPT12 filament formation, leading to loss of the sperm annulus/septin ring and poor male fertility. Thus, we provide the first in vivo genetic evidence characterizing importance of septin phosphorylation in the assembly, cellular function and physiological significance of septins.
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yi-Ru
authors.initials: YR
authors.lastname: Shen
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Han-Yu
authors.initials: HY
authors.lastname: Wang
authors.affiliation: Department of Biochemistry and Molecular Cell Biology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
authors.forename: Yung-Che
authors.initials: YC
authors.lastname: Kuo
authors.affiliation: Department of Biochemistry and Molecular Biology, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Shih-Chuan
authors.initials: SC
authors.lastname: Shih
authors.affiliation: Department of Agricultural Chemistry, National Taiwan University, Taipei, Taiwan.
authors.forename: Chun-Hua
authors.identifier: 0000-0002-0008-7383
authors.initials: CH
authors.lastname: Hsu
authors.affiliation: Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan.
authors.forename: Yet-Ran
authors.initials: YR
authors.lastname: Chen
authors.affiliation: Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Shang-Rung
authors.initials: SR
authors.lastname: Wu
authors.affiliation: Department of Cell Biology and Anatomy, College of Medicine, National Cheng Kung University, Tainan, Taiwan.|The Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chia-Yih
authors.initials: CY
authors.lastname: Wang
authors.affiliation: Department of Obstetrics and Gynecology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.|Department of Biochemistry and Molecular Biology, National Cheng Kung University, Tainan, Taiwan.|The Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Pao-Lin
authors.identifier: 0000-0002-0726-1030
authors.initials: PL
authors.lastname: Kuo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D057809:HEK293 Cells; D006801:Humans; D007150:Immunohistochemistry; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D009154:Mutation; D010766:Phosphorylation; D058112:Septins / Q000235:genetics* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D012694:Serine / Q000235:genetics / Q000378:metabolism; D013081:Sperm Motility / Q000235:genetics*; D013094:Spermatozoa / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D012694:Serine; C555146:SEPT12 protein, mouse; D058112:Septins