title: Developmental regulation of pp44/46, tyrosine-phosphorylated proteins associated with tyrosine/serine kinase activity in Trypanosoma brucei.
abstract: The pattern of tyrosine-phosphorylated proteins is developmentally regulated in Trypanosoma brucei. To examine the function and regulation of these tyrosine-phosphorylated molecules, monoclonal antibodies were generated using purified tyrosine-phosphorylated proteins as immunogens. Two monoclonal antibodies were obtained. Both react with a set of proteins at 44-46 kDa, collectively referred to as pp44/46, that are phosphorylated on serine and tyrosine. Differentiation of the parasite from slender bloodforms to procyclic forms was accompanied by increased abundance and tyrosine-phosphorylation of pp44/46. The monoclonal antibodies immunoprecipitated protein kinase activity capable of phosphorylating pp44/46 on serine and tyrosine, and myelin basic protein on serine. The data indicate that the prominent tyrosine-phosphorylated proteins induced upon differentiation are either themselves protein kinases or that they are associated with protein kinases.
authors.affiliation: Seattle Biomedical Research Institute, WA 98109.
authors.forename: M
authors.initials: M
authors.lastname: Parsons
authors.forename: J A
authors.initials: JA
authors.lastname: Ledbetter
authors.forename: G L
authors.initials: GL
authors.lastname: Schieven
authors.forename: A E
authors.initials: AE
authors.lastname: Nel
authors.forename: S B
authors.initials: SB
authors.lastname: Kanner
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D015800:Protozoan Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D012694:Serine / Q000737:chemistry; D014346:Trypanosoma brucei brucei / Q000254:growth & development / Q000378:metabolism*; D014443:Tyrosine / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D015800:Protozoan Proteins; D014443:Tyrosine; D012694:Serine; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases