Differential subcellular distribution of mortalin in mortal and immortal mouse and human fibroblasts.
Mortalin, p66mot-1, from the cytosolic fractions of mouse embryonic fibroblasts (MEF) has been identified. We have cloned and characterized it as a novel member of mouse hsp70 family [R. Wadhwa, S. C. Kaul, Y. Ikawa, and Y. Sugimoto (1993) J. Biol. Chem. 268, 6615-6621]. We report that immortal clones from MEF such as NIH 3T3, RS4, and Balb/c 3T3 harbor the same or a very similar protein but in the perinuclear locale. Biochemical analysis revealed that the proteins from mortal (MEF) and immortal (NIH 3T3) fibroblasts do not show gross differences. However, the phenomenon of differential distribution of p66 protein in mortal and immortal fibroblasts is conserved in three different strains of mouse and, interestingly, in human fibroblasts, too. The data suggest that at least one common step is involved in immortalization of mouse and human fibroblasts and also point to the practical implication(s) of such easily detectable differences.
Wadhwa
R
R
National Institute of Bioscience and Human-Technology, Agency of Industrial Science and Technology, Ibaraki, Japan.
Kaul
S C
SC
Mitsui
Y
Y
Sugimoto
Y
Y
D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins; D002460:Cell Line; D005347:Fibroblasts / Q000737:chemistry* / Q000166:cytology; D005354:Fibrosarcoma / Q000737:chemistry / Q000473:pathology; D005455:Fluorescent Antibody Technique; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D051379:Mice; D008807:Mice, Inbred BALB C; D024101:Mitochondrial Proteins; D011233:Precipitin Tests
D002352:Carrier Proteins; D018840:HSP70 Heat-Shock Proteins; C492001:HSPA9 protein, human; D006360:Heat-Shock Proteins; C083794:Hspa9 protein, mouse; D024101:Mitochondrial Proteins; C080352:mortalin