TY - JOUR
T1 - Ubiquitous expression and cell cycle regulation of the protein kinase PIM-1
AU - Liang, Hong
AU - Hittelman, Walter
AU - Nagarajan, Lalitha
N1 - Funding Information:
This work was supported by Public Health Service Grant CA-49765 (to L.N.) and core Grant CA 16672 to M. D. Anderson Cancer Center. We thank Rosemarie Lauzon for assistance with manuscript preparation.
PY - 1996/6/15
Y1 - 1996/6/15
N2 - The murine pim-1 gene, isolated as a locus frequently activated, by proviral integration in T cell lymphomas, encodes a protein serine kinase. Although genetic evidence suggests a crucial role for this protooncogene in cell growth and transformation, very little is known about its protein product. The murine pim-1 mRNA provides alternate translational starts at a CUG codon +87-89 and an AUG codon at +339-341, in the same open reading frame (ORF), resulting in 44-kDa (397 amino acids) and 34-kDa (313 amino acids) isoforms. In this report, we demonstrate that the human PIM-1 mRNA is translated only from the single initiation methionine codon at +339-341 under cell-free conditions. Immunoblotting analyses of several human solid tumor cell lines, with highly specific antisera reveal two ubiquitously expressed isoforms (35 and 34 kDa). The estimated half-life of these proteins is shorter in the normal peripheral blood leukocytes (<5 min) than in the chronic myelogenous leukemia cells K562 (<20 min). Immunoblotting analyses of centrifugally elutriated fractions of the chronic myelogenous leukemia BV173 cells demonstrate that the levels of PIM-1 increase during the progression from early to late G1, remain high at the G1/S boundary and G2 phases of the cell cycle. The results presented here suggest a ubiquitous role for PIM-1 in progression through cell cycle.
AB - The murine pim-1 gene, isolated as a locus frequently activated, by proviral integration in T cell lymphomas, encodes a protein serine kinase. Although genetic evidence suggests a crucial role for this protooncogene in cell growth and transformation, very little is known about its protein product. The murine pim-1 mRNA provides alternate translational starts at a CUG codon +87-89 and an AUG codon at +339-341, in the same open reading frame (ORF), resulting in 44-kDa (397 amino acids) and 34-kDa (313 amino acids) isoforms. In this report, we demonstrate that the human PIM-1 mRNA is translated only from the single initiation methionine codon at +339-341 under cell-free conditions. Immunoblotting analyses of several human solid tumor cell lines, with highly specific antisera reveal two ubiquitously expressed isoforms (35 and 34 kDa). The estimated half-life of these proteins is shorter in the normal peripheral blood leukocytes (<5 min) than in the chronic myelogenous leukemia cells K562 (<20 min). Immunoblotting analyses of centrifugally elutriated fractions of the chronic myelogenous leukemia BV173 cells demonstrate that the levels of PIM-1 increase during the progression from early to late G1, remain high at the G1/S boundary and G2 phases of the cell cycle. The results presented here suggest a ubiquitous role for PIM-1 in progression through cell cycle.
KW - Cell cycle
KW - Protein kinase PIM-1
KW - Turn over
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U2 - 10.1006/abbi.1996.0251
DO - 10.1006/abbi.1996.0251
M3 - Article
C2 - 8660654
AN - SCOPUS:0029943649
SN - 0003-9861
VL - 330
SP - 259
EP - 265
JO - Archives of Biochemistry and Biophysics
JF - Archives of Biochemistry and Biophysics
IS - 2
ER -