TPI-2 expression in mitogen stimulated human lymphocytes

Conference · Thu May 01 00:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5176882

Old, S E; Landa, L; Mohrenweiser, H W

An electrophoretically unique isozyme of triosephosphate isomerase is observed in proliferating human cells. The expression of the proliferation specific TPI-2 subunit, which is a product of the same structural locus as the constitutive subunit (TPI-1), is restricted to hominoid species. Total TPI activity increases 2-4 fold within 6-12 hrs of mitogen stimulation of human peripheral lymphocytes. TPI-2 is observed at 12 hrs and accounts for 30% of the total TPI activity at 48-60 hrs following stimulation. The appearance of TPI-2 is dependent upon RNA synthesis but not DNA synthesis. Calcium ionophore, interleukin-2 and phorbol ester do not induce TPI-2 and do not enhance the level of mitogen induced expression. Cyclosporine and dexamethasone inhibit the mitogen induced increase in TPI-2 and total TPI activity. The 5-10 fold increase in TPI mRNA following mitogen stimulation occurs before the increase in TPI activity. Only a single size TPI mRNA species (1250 bases) is detected in peripheral lymphocytes and transformed lymphoblasts of human origin as well as in rapidly dividing cells from Vero, the latter a non TPI-2 expressing primate species. The mechanism for generation of the proliferation specific subunit, from the same structural locus as the constitutive enzyme, is still undefined although the regulation of TPI-2 expression in human cells has characteristics similar to other cell proliferation specific loci.

• Research Organization: Univ. of Michigan Medical School, Ann Arbor
• OSTI ID: 5176882
• Report Number(s): CONF-8606151-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
• Country of Publication: United States
• Language: English

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