Pseudouridylate synthase that catalyzes pseudouridylation of tRNAs and mRNAs (PubMed:15772074, PubMed:24722331). Acts on positions 27/28 in the anticodon stem and also positions 34 and 36 in the anticodon of an intron containing tRNA (PubMed:24722331). Also catalyzes pseudouridylation of mRNAs: mediates pseudouridylation of mRNAs with the consensus sequence 5'-UGUAG-3' (PubMed:31477916, PubMed:35051350). Acts as a regulator of pre-mRNA splicing by mediating pseudouridylation of pre-mRNAs at loca

MitochondrionNucleusCytoplasm

Myopathy with lactic acidosis and sideroblastic anemia 1

A rare oxidative phosphorylation disorder specific to skeletal muscle and bone marrow. Affected individuals manifest progressive muscle weakness, exercise intolerance, lactic acidosis, sideroblastic anemia and delayed growth.

Acts as a co-chaperone in iron-sulfur cluster assembly in mitochondria (PubMed:20668094). Required for incorporation of iron-sulfur clusters into SDHB, the iron-sulfur protein subunit of succinate dehydrogenase that is involved in complex II of the mitochondrial electron transport chain (PubMed:26749241). Recruited to SDHB by interaction with SDHAF1 which first binds SDHB and then recruits the iron-sulfur transfer complex formed by HSC20, HSPA9 and ISCU through direct binding to HSC20 (PubMed:26

CytoplasmMitochondrion

Anemia, sideroblastic, 5

A form of sideroblastic anemia, a bone marrow disorder defined by the presence of pathologic iron deposits in erythroblast mitochondria. Sideroblastic anemia is characterized by anemia of varying severity, hypochromic peripheral erythrocytes, systemic iron overload secondary to chronic ineffective erythropoiesis, and the presence of bone marrow ringed sideroblasts. Sideroblasts are characterized by iron-loaded mitochondria clustered around the nucleus. SIDBA5 inheritance is autosomal recessive.

Catalyzes the attachment of tyrosine to tRNA(Tyr) in a two-step reaction: tyrosine is first activated by ATP to form Tyr-AMP and then transferred to the acceptor end of tRNA(Tyr)

Mitochondrion matrix

Myopathy with lactic acidosis and sideroblastic anemia 2

A rare oxidative phosphorylation disorder specific to skeletal muscle and bone marrow. Affected individuals manifest sideroblastic anemia, progressive lethargy, muscle weakness, and exercise intolerance associated with persistent lactic acidemia.

Monothiol glutaredoxin involved in mitochondrial iron-sulfur (Fe/S) cluster transfer (PubMed:20364084, PubMed:23615440). Receives 2Fe/2S clusters from scaffold protein ISCU and mediates their transfer to apoproteins, to the 4Fe/FS cluster biosynthesis machinery, or export from mitochondrion (PubMed:20364084, PubMed:23615440, PubMed:24334290). Required for normal regulation of hemoglobin synthesis by the iron-sulfur protein ACO1 (PubMed:20364084)

Mitochondrion matrix

Anemia, sideroblastic, 3, pyridoxine-refractory

A form of sideroblastic anemia, a bone marrow disorder defined by the presence of pathologic iron deposits in erythroblast mitochondria. Sideroblastic anemia is characterized by anemia of varying severity, hypochromic peripheral erythrocytes, systemic iron overload secondary to chronic ineffective erythropoiesis, and the presence of bone marrow ringed sideroblasts. Sideroblasts are characterized by iron-loaded mitochondria clustered around the nucleus. SIDBA3 is refractory to treatment with vitamin B6, while iron chelation therapy may result in clinical improvement. SIDBA3 inheritance is autosomal recessive.

Mitochondrial chaperone that plays a key role in mitochondrial protein import, folding, and assembly. Plays an essential role in the protein quality control system, the correct folding of proteins, the re-folding of misfolded proteins, and the targeting of proteins for subsequent degradation. These processes are achieved through cycles of ATP binding, ATP hydrolysis, and ADP release, mediated by co-chaperones (PubMed:18632665, PubMed:25615450, PubMed:28848044, PubMed:30933555, PubMed:31177526).

MitochondrionNucleus, nucleolusCytoplasmMitochondrion matrix

Anemia, sideroblastic, 4

A form of sideroblastic anemia, a bone marrow disorder defined by the presence of pathologic iron deposits in erythroblast mitochondria. Sideroblastic anemia is characterized by anemia of varying severity, hypochromic peripheral erythrocytes, systemic iron overload secondary to chronic ineffective erythropoiesis, and the presence of bone marrow ringed sideroblasts. Sideroblasts are characterized by iron-loaded mitochondria clustered around the nucleus. SIDBA4 has been reported to be inherited as an autosomal recessive disease, with a pseudodominant pattern of inheritance in some families.

Mitochondrial glycine transporter that imports glycine into the mitochondrial matrix. Plays an important role in providing glycine for the first enzymatic step in heme biosynthesis, the condensation of glycine with succinyl-CoA to produce 5-aminolevulinate (ALA) in the mitochondrial matrix. Required during erythropoiesis Plays a role as pro-apoptotic protein that induces caspase-dependent apoptosis

Mitochondrion inner membrane

Anemia, sideroblastic, 2, pyridoxine-refractory

A form of sideroblastic anemia not responsive to pyridoxine. Sideroblastic anemia is characterized by anemia of varying severity, hypochromic peripheral erythrocytes, systemic iron overload secondary to chronic ineffective erythropoiesis, and the presence of bone marrow ringed sideroblasts. Sideroblasts are characterized by iron-loaded mitochondria clustered around the nucleus.

Nucleotidyltransferase that catalyzes the addition and repair of the essential 3'-terminal CCA sequence in tRNAs, which is necessary for the attachment of amino acids to the 3' terminus of tRNA molecules, using CTP and ATP as substrates (PubMed:11504732, PubMed:25193871, PubMed:25640237, PubMed:25652405, PubMed:29454993, PubMed:30959222, PubMed:31011209, PubMed:34023389). tRNA 3'-terminal CCA addition is required both for tRNA processing and repair (PubMed:22076379, PubMed:25640237). Promotes tR

MitochondrionCytoplasmNucleus

Sideroblastic anemia with B-cell immunodeficiency, periodic fevers, and developmental delay

An autosomal recessive disease characterized by severe sideroblastic anemia with onset in the neonatal period or infancy, recurrent periodic fevers without an infectious etiology, B-cell lymphopenia and hypogammaglobulinemia. Affected individuals show delayed psychomotor development with variable neurodegeneration. Additional variable features include sensorineural hearing loss, retinitis pigmentosa, nephrocalcinosis, and cardiomyopathy.

Exports glutathione-coordinated iron-sulfur clusters such as [2Fe-2S]-(GS)4 cluster from the mitochondria to the cytosol in an ATP-dependent manner allowing the assembly of the cytosolic iron-sulfur (Fe/S) cluster-containing proteins and participates in iron homeostasis (PubMed:10196363, PubMed:17192393, PubMed:33157103). Moreover, through a functional complex formed of ABCB7, FECH and ABCB10, also plays a role in the cellular iron homeostasis, mitochondrial function and heme biosynthesis (PubMe

Mitochondrion inner membrane

Spinocerebellar ataxia, X-linked 6, with or without sideroblastic anemia

An X-linked recessive disorder characterized by an infantile to early childhood onset of non-progressive cerebellar ataxia and mild anemia, with hypochromia and microcytosis.

Catalyzes the pyridoxal 5'-phosphate (PLP)-dependent condensation of succinyl-CoA and glycine to form aminolevulinic acid (ALA), with CoA and CO2 as by-products (PubMed:14643893, PubMed:21252495, PubMed:21309041, PubMed:21653323, PubMed:32499479, PubMed:34492704). Contributes significantly to heme formation during erythropoiesis (PubMed:2050125) Catalyzes the pyridoxal 5'-phosphate (PLP)-dependent condensation of succinyl-CoA and glycine to form aminolevulinic acid (ALA), with CoA and CO2 as by-

Mitochondrion inner membrane

Anemia, sideroblastic, 1

A form of sideroblastic anemia that shows a variable hematologic response to pharmacologic doses of pyridoxine. Sideroblastic anemia is characterized by anemia of varying severity, hypochromic peripheral erythrocytes, systemic iron overload secondary to chronic ineffective erythropoiesis, and the presence of bone marrow ringed sideroblasts. Sideroblasts are characterized by iron-loaded mitochondria clustered around the nucleus.

Integral membrane protein that functions as a NADPH-dependent ferric-chelate reductase, using NADPH from one side of the membrane to reduce a Fe(3+) chelate that is bound on the other side of the membrane (PubMed:26205815). Mediates sequential transmembrane electron transfer from NADPH to FAD and onto heme, and finally to the Fe(3+) chelate (By similarity). Can also reduce Cu(2+) to Cu(1+) (By similarity). Mediates efficient transferrin-dependent iron uptake in erythroid cells (By similarity). M

Endosome membrane

Anemia, hypochromic microcytic, with iron overload 2

A hematologic disease characterized by abnormal hemoglobin content in the erythrocytes which are reduced in size, severe anemia, erythropoietic hyperplasia of bone marrow, massive hepatic iron deposition, and hepatosplenomegaly.