SksC, a fertilization-related protein kinase in Chlamydomonas, is expressed throughout the cell cycle and gametogenesis,and a phosphorylated form is present in both flagella and cell bodies

• Published in: Biochemical and biophysical research communications 1996-11, Vol.228 (1), p.45-54
• Main Authors: Kurvari, V, Snell, W J
• Format: Article
• Language: English
• Subjects: Animals; cell division; cell structure; chemistry; chimie; Chlamydomonas - enzymology; Chlamydomonas - genetics; Chlamydomonas - growth & development; Chlamydomonas - physiology; chlamydomonas reinhardtii; Cloning, Molecular; division cellulaire; division celular; estructura celular; expresion genica; expression des genes; fecondation; fecundacion; fertilization; Flagella - enzymology; Flagella - physiology; fosfoproteinas; fosforilacion; gamete; gametes; gametogenese; Gametogenesis; gametos; gene expression; Gene Expression Regulation, Developmental; Genes, Protozoan; immunologie; immunology; inmunologia; periode vegetative; periodo vegetativo; phosphoproteine; phosphoproteins; Phosphorylation; Plant Proteins; protein kinase; Protein Kinases - metabolism; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Protein-Tyrosine Kinases - genetics; Protein-Tyrosine Kinases - metabolism; proteina quinasa; proteine kinase; quimica; RNA, Messenger - genetics; RNA, Messenger - metabolism; RNA, Protozoan - genetics; RNA, Protozoan - metabolism; Signal Transduction; structure cellulaire; transcripcion; transcription; vegetative period
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1996.1614

Fertilization in the biflagellated eukaryote, Chlamydomonas, is initiated by flagellar adhesion between gametes of opposite mating types. An early event in the signal transduction pathway induced by these cell-cell interactions is the rapid inactivation of a flagellar protein kinase that phosphorylates a 48 kDa flagellar protein. Molecular cloning and characterization indicates that the 48 kDa substrate, termed SksC, itself is a novel protein kinase. Here, we have determined that its transcript levels were unchanged during prolonged flagellar adhesion. Moreover, resynthesis of new flagellar proteins following deflagellation was not accompanied by increases in transcript levels of SksC, suggesting that expression of this soluble protein kinase might not be restricted to flagella. Immunoblot analysis indicated that expression of SksC was ubiquitous: this soluble protein was found in both flagella and cell bodies and was expressed throughout the cell cycle and gametogenesis. Immunoprecipitation experiments indicated that SksC was phosphorylated in both flagella and cell bodies. Thus, in addition to its potential role in fertilization, this novel protein kinase may play a role in other signaling events in Chlamydomonas.