TY - JOUR
T1 - Interaction between succinyl CoA synthetase and the heme-biosynthetic enzyme ALAS-E is disrupted in sideroblastic anemia
AU - Furuyama, Kazumichi
AU - Sassa, Shigeru
PY - 2000/3
Y1 - 2000/3
N2 - The first and the rate-limiting enzyme of heme biosynthesis is δ- aminolevulinate synthase (ALAS), which is localized in mitochondria. There are 2 tissue-specific isoforms of ALAS, erythroid-specific (ALAS-E) and nonspecific ALAS (ALAS-N). To identify possible mitochondrial factors that modulate ALAS-E function, we screened a human bone marrow cDNA library, using the mitochondrial form of human ALAS-E as a bait protein in the yeast 2- hybrid system. Our screening led to the isolation of the β subunit of human ATP-specific succinyl CoA synthetase (SCS-βA). Using transient expression and coimmunoprecipitation, we verified that mitochodrially expressed SCS-βA associates specifically with ALAS-E and not with ALAS-N. Furthermore, the ALAS-E mutants R411C and M426V associated with SCS-βA, but the D190V mutant did not. Because the D190V mutant was identified in a patient with pyridoxine-refractory X-linked sideroblastic anemia, our findings suggest that appropriate association of SCS-βA and ALAS-E promotes efficient use of succinyl CoA by ALAS-E or helps translocate ALAS-E into mitochondria.
AB - The first and the rate-limiting enzyme of heme biosynthesis is δ- aminolevulinate synthase (ALAS), which is localized in mitochondria. There are 2 tissue-specific isoforms of ALAS, erythroid-specific (ALAS-E) and nonspecific ALAS (ALAS-N). To identify possible mitochondrial factors that modulate ALAS-E function, we screened a human bone marrow cDNA library, using the mitochondrial form of human ALAS-E as a bait protein in the yeast 2- hybrid system. Our screening led to the isolation of the β subunit of human ATP-specific succinyl CoA synthetase (SCS-βA). Using transient expression and coimmunoprecipitation, we verified that mitochodrially expressed SCS-βA associates specifically with ALAS-E and not with ALAS-N. Furthermore, the ALAS-E mutants R411C and M426V associated with SCS-βA, but the D190V mutant did not. Because the D190V mutant was identified in a patient with pyridoxine-refractory X-linked sideroblastic anemia, our findings suggest that appropriate association of SCS-βA and ALAS-E promotes efficient use of succinyl CoA by ALAS-E or helps translocate ALAS-E into mitochondria.
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U2 - 10.1172/JCI6816
DO - 10.1172/JCI6816
M3 - Article
C2 - 10727444
AN - SCOPUS:0034068564
VL - 105
SP - 757
EP - 764
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
SN - 0021-9738
IS - 6
ER -