Unique behavior of a dictyostelium homologue of TRAP-1, coupling with differentiation of D. discoideum cells.
Dd-TRAP1 is a Dictyostelium homologue of TRAP-1, a human protein that binds to the type 1 tumor necrosis factor (TNF) receptor. TRAP-1 has a putative mitochondrial localization sequence and shows significant homology to members of the HSP90 family. Although TRAP-1 is mainly localized to mitochondria in several mammalian cells, in certain tissues it is also localized at specific extramitochondrial sites. In Dictyostelium cells, Dd-TRAP1 is predominantly located in the cell membrane/cortex during growth and just after starvation. Double staining of vegetatively growing cells with the anti-Dd-TRAP1 antibody and TRITC-phalloidin has demonstrated colocalization of Dd-TRAP1 and F-actin at the leading edge of cortical protrusions such as pseudopodes. Coupled with differentiation, however, Dd-TRAP1 located at the cortical region is translocated to mitochondria in spite of the absence of the mitochondrial localization sequence at its N-terminus. The translocation of this protein raises interesting and fundamental questions regarding possible mechanisms by which Dd-TRAP1 is involved in cellular differentiation.
Morita
Tsuyoshi
T
Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aoba, Sendai 980-8578, Japan. tsuyo@biology.tohoku.ac.jp
Amagai
Aiko
A
Maeda
Yasuo
Y
D000199:Actins / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D017124:Conserved Sequence; D017077:Culture Media, Conditioned / Q000378:metabolism; D004023:Dictyostelium / Q000737:chemistry / Q000254:growth & development*; D018841:HSP90 Heat-Shock Proteins / Q000032:analysis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008928:Mitochondria / Q000378:metabolism; D008969:Molecular Sequence Data; D010590:Phalloidine / Q000378:metabolism; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012235:Rhodamines / Q000378:metabolism; D016415:Sequence Alignment; D013347:Subcellular Fractions / Q000378:metabolism; D014170:Transformation, Genetic
D000199:Actins; D017077:Culture Media, Conditioned; D018841:HSP90 Heat-Shock Proteins; D011993:Recombinant Fusion Proteins; D012235:Rhodamines; C092306:TRAP1 protein, human; D010590:Phalloidine; C009434:tetramethylrhodamine isothiocyanate