Identification of the human pim-1 gene product as a 33-kilodalton cytoplasmic protein with tyrosine kinase activity.
The human pim-1 gene was recently identified as a new putative oncogene located on chromosome 6p21, a region showing karyotypic abnormalities in particular leukemias. In the present work we characterized the pim protein product. In vitro translation of positively selected poly(A)+ mRNA indicates that this gene encodes a 33-kilodalton protein. Anti-pim antibodies were raised against a fused TrpE-pim protein induced in a bacterial expression vector. This antibody immunoprecipitated a 33-kilodalton protein from in vivo [35S]methionine-labeled K562 and KCl myelogenous origin cell lines. This protein was localized to the cytoplasm, and in vivo labeling as well as in vitro kinase assay suggests that it is a phosphoprotein with tyrosine kinase activity. This was further confirmed by performing autophosphorylation directly on a p33pim-containing gel band cut out after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The results imply that the tyrosine kinase activity of pim can be recovered after boiling the pim-1 protein in sample buffer: a feature not described yet for this class of protein. These results suggest that pim-1 is a new member of the subgroup of oncogenes encoding tyrosine kinases.
Telerman
A
A
Department of Chemical Immunology, Weizmann Institute of Science, Rehovot, Israel.
Amson
R
R
Zakut-Houri
R
R
Givol
D
D
D002460:Cell Line; D002896:Chromosomes, Human, Pair 6; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000201:enzymology; D004262:DNA Restriction Enzymes; D005796:Genes; D005822:Genetic Vectors; D006801:Humans; D008970:Molecular Weight; D009857:Oncogenes; D011505:Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases; D004262:DNA Restriction Enzymes