title: SPE-8, a protein-tyrosine kinase, localizes to the spermatid cell membrane through interaction with other members of the SPE-8 group spermatid activation signaling pathway in C. elegans.
abstract: BACKGROUND
  The SPE-8 group gene products transduce the signal for spermatid activation initiated by extracellular zinc in C. elegans. Mutations in the spe-8 group genes result in hermaphrodite-derived spermatids that cannot activate to crawling spermatozoa, although spermatids from mutant males activate through a pathway induced by extracellular TRY-5 protease present in male seminal fluid.
  
  
  RESULTS
  Here, we identify SPE-8 as a member of a large family of sperm-expressed non-receptor-like protein-tyrosine kinases. A rescuing SPE-8::GFP translational fusion reporter localizes to the plasma membrane in all spermatogenic cells from the primary spermatocyte stage through spermatids. Once spermatids become activated to spermatozoa, the reporter moves from the plasma membrane to the cytoplasm. Mutations in the spe-8 group genes spe-12, spe-19, and spe-27 disrupt localization of the reporter to the plasma membrane, while localization appears near normal in a spe-29 mutant background.
  
  
  CONCLUSIONS
  These results suggest that the SPE-8 group proteins form a functional complex localized at the plasma membrane, and that SPE-8 is correctly positioned only when all members of the SPE-8 group are present, with the possible exception of SPE-29. Further, SPE-8 is released from the membrane when the activation signal is transduced into the spermatid.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Muhlrad
authors.forename: Jessica N
authors.initials: JN
authors.lastname: Clark
authors.forename: Ubaydah
authors.initials: U
authors.lastname: Nasri
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Sullivan
authors.affiliation: Department of Biological Science, California State Polytechnic University, 3801 W, Temple Ave, Pomona, CA 91768, USA. cwlamunyon@csupomona.edu.
authors.forename: Craig W
authors.initials: CW
authors.lastname: LaMunyon
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000201:enzymology* / Q000235:genetics; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology*; D018509:DNA, Helminth / Q000235:genetics; D005091:Exons; D008297:Male; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D013087:Spermatids / Q000201:enzymology*
chemical_list: D029742:Caenorhabditis elegans Proteins; D018509:DNA, Helminth; C581871:SPE-8 protein, C elegans; D011505:Protein-Tyrosine Kinases