ENHANCEMENT OF COPROPORPHYRINOGEN-III TRANSPORT INTO ISOLATED TRANSFORMED LEUKOCYTE MITOCHONDRIA BY ATP

It has been proposed that in normal animal cells, biosynthesis of the heme precursor protoporphyrin IX (Proto) requires cooperation between the mitochondria and cytoplasm [S. Granick (1967) in Biochemistry of t he Chloroplast (Goodwin, T. W., Ed.), pp. 373-410, Academic Press, NY] . In this work, the conversion of ALA to Coprogen in the cytoplasm of MLA 144 cells (a retrovirally transformed gibbon ape leukemic T cell l ine) is demonstrated, This in turn indicates that the intracellular lo calization of Coprogen biosynthesis in transformed animal cells is sim ilar to that proposed for normal animal cells. It is also shown that i n MLA 144 cells, after ALA conversion to Coprogen in the cytoplasm, Co progen is transported into the mitochondria; via an ATP-dependent proc ess. The possible involvement of the mitochondrial peripheral-type ben zodliazepine receptor (M-PBR) in Coprogen transport into mitochondria is discussed. (C) 1996 Academic Press, Inc.