Involving of the cytoplasmic region of leukemia inhibitory factor receptoralpha subunit, IL-6 related signal transducer-gp130 or Fas death domain for MAPK p42/44 activation in HL-60 cell with LIF or anti-Fas IgG

The chimeric receptors were prepared by exchanging the cytoplasmic region b etween leukemia inhibitory factor (LIF) receptor alpha subunit (gp190) and the other subunit-gp130 (190/130,130/190) and separately transduced into le ukemia line HL-60 (to have the wild type subunit). The purpose is to invest igate which subunit for activating MAPK p42/44 in leukemia cell while the c ytoplasmic region homodimerization (190cyt-190cyt, 130cyt-130cyt) was induc ed by LIF. The results showed that MAPK p42/44 expression level after LIF s timulation 5 h was lower in the transformants with pED 130/190 (190cyt-190c yt) (p < 0.01) and higher in the transformants with pED 190/130 (130cyt-130 cyt) (p < 0.05) than those in the parent cells. Meanwhile, MAPK p42/44 phos phorylation (Thr202/Tyr204) was ascended and the highest at 10 min in the 1 90/130 and descended in the 130/190. It suggests that gp130 activate MAPK p 42/44 and gp190 indirectly regulate its expression and function. In order t o analyses the relation of the subunit oligomerization and MAPK p42/44 we a lso prepared the recombination of the extracellular and transmembrane regio n of Fas and the cytoplasmic region of each LIFR subunit (Fas/190, Fas/130) . After transduction into HL-60 with lipofection and induction by anti-Fas IgG, we found that MAPK p42/44 expression levels were lower in the Fas/190 than in the Fas/130 and parent cells (p < 0.01) and no difference between t he Fas/130 and the wild type receptor. However, phospho-MAPK p42/44 were in creased in the Fas/130 than the parent cells. It suggests that the oligomer ization of the cytoplasmic regions of gp130 be potential to normally initia te MAPK p42/44 for the signal of HL-60 proliferation. We also determine tha t the separated oligomerization FasDD (no dimerization) can initiate the co rresponding signal molecules, then regulate MAPK p42/44 expression and phos phorylation in leukemia cells.