Abstract
Erythrocyte precursors produce abundant α- and β-globin proteins, which assemble with each other to form hemoglobin A (HbA), the major blood oxygen carrier. αHb-stabilizing protein (AHSP) binds free α subunits reversibly to maintain their structure and limit their ability to generate reactive oxygen species. Accordingly, loss of AHSP aggravates the toxicity of excessive free α-globin caused by β-globin gene disruption in mice. Surprisingly, we found that AHSP also has important functions when free α-globin is limited. Thus, compound mutants lacking both Ahsp and 1 of 4 α-globin genes (genotype Ahsp-/-α-globin -/-α/αα) exhibited more severe anemia and Hb instability than mice with either mutation alone. In vitro, recombinant AHSP promoted folding of newly translated α-globin, enhanced its refolding after denaturation, and facilitated its incorporation into HbA. Moreover, in erythroid precursors, newly formed free α-globin was destabilized by loss of AHSP. Therefore, in addition to its previously defined role in detoxification of excess α-globin, AHSP also acts as a molecular chaperone to stabilize nascent α-globin for HbA assembly. Our findings illustrate what we believe to be a novel adaptive mechanism by which a specialized cell coordinates high-level production of a multisubunit protein and protects against various synthetic imbalances.
| Original language | English |
|---|---|
| Pages (from-to) | 1856-1865 |
| Number of pages | 10 |
| Journal | Journal of Clinical Investigation |
| Volume | 117 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2 Jul 2007 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Medicine(all)
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An erythroid chaperone that facilitates folding of α-globin subunits for hemoglobin synthesis. / Yu, Xiang; Kong, Yi; Dore, Louis C.; Abdulmalik, Osheiza; Katein, Anne M.; Zhou, Suiping; Choi, John K.; Gell, David; Mackay, Joel P.; Gow, Andrew J.; Weiss, Mitchell J.
In: Journal of Clinical Investigation, Vol. 117, No. 7, 02.07.2007, p. 1856-1865.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - An erythroid chaperone that facilitates folding of α-globin subunits for hemoglobin synthesis
AU - Yu, Xiang
AU - Kong, Yi
AU - Dore, Louis C.
AU - Abdulmalik, Osheiza
AU - Katein, Anne M.
AU - Zhou, Suiping
AU - Choi, John K.
AU - Gell, David
AU - Mackay, Joel P.
AU - Gow, Andrew J.
AU - Weiss, Mitchell J.
PY - 2007/7/2
Y1 - 2007/7/2
N2 - Erythrocyte precursors produce abundant α- and β-globin proteins, which assemble with each other to form hemoglobin A (HbA), the major blood oxygen carrier. αHb-stabilizing protein (AHSP) binds free α subunits reversibly to maintain their structure and limit their ability to generate reactive oxygen species. Accordingly, loss of AHSP aggravates the toxicity of excessive free α-globin caused by β-globin gene disruption in mice. Surprisingly, we found that AHSP also has important functions when free α-globin is limited. Thus, compound mutants lacking both Ahsp and 1 of 4 α-globin genes (genotype Ahsp-/-α-globin -/-α/αα) exhibited more severe anemia and Hb instability than mice with either mutation alone. In vitro, recombinant AHSP promoted folding of newly translated α-globin, enhanced its refolding after denaturation, and facilitated its incorporation into HbA. Moreover, in erythroid precursors, newly formed free α-globin was destabilized by loss of AHSP. Therefore, in addition to its previously defined role in detoxification of excess α-globin, AHSP also acts as a molecular chaperone to stabilize nascent α-globin for HbA assembly. Our findings illustrate what we believe to be a novel adaptive mechanism by which a specialized cell coordinates high-level production of a multisubunit protein and protects against various synthetic imbalances.
AB - Erythrocyte precursors produce abundant α- and β-globin proteins, which assemble with each other to form hemoglobin A (HbA), the major blood oxygen carrier. αHb-stabilizing protein (AHSP) binds free α subunits reversibly to maintain their structure and limit their ability to generate reactive oxygen species. Accordingly, loss of AHSP aggravates the toxicity of excessive free α-globin caused by β-globin gene disruption in mice. Surprisingly, we found that AHSP also has important functions when free α-globin is limited. Thus, compound mutants lacking both Ahsp and 1 of 4 α-globin genes (genotype Ahsp-/-α-globin -/-α/αα) exhibited more severe anemia and Hb instability than mice with either mutation alone. In vitro, recombinant AHSP promoted folding of newly translated α-globin, enhanced its refolding after denaturation, and facilitated its incorporation into HbA. Moreover, in erythroid precursors, newly formed free α-globin was destabilized by loss of AHSP. Therefore, in addition to its previously defined role in detoxification of excess α-globin, AHSP also acts as a molecular chaperone to stabilize nascent α-globin for HbA assembly. Our findings illustrate what we believe to be a novel adaptive mechanism by which a specialized cell coordinates high-level production of a multisubunit protein and protects against various synthetic imbalances.
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U2 - 10.1172/JCI31664
DO - 10.1172/JCI31664
M3 - Article
VL - 117
SP - 1856
EP - 1865
JO - Journal of Clinical Investigation
JF - Journal of Clinical Investigation
SN - 0021-9738
IS - 7
ER -