Developmental regulation of pp44/46, tyrosine-phosphorylated proteins associated with tyrosine/serine kinase activity in Trypanosoma brucei.
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.
Parsons
M
M
Seattle Biomedical Research Institute, WA 98109.
Ledbetter
J A
JA
Schieven
G L
GL
Nel
A E
AE
Kanner
S B
SB
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
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