AMBP_MERUN
ID AMBP_MERUN Reviewed; 346 AA.
AC Q62577; Q62576;
DT 01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1997, sequence version 1.
DT 03-AUG-2022, entry version 105.
DE RecName: Full=Protein AMBP;
DE Contains:
DE RecName: Full=Alpha-1-microglobulin;
DE EC=1.6.2.- {ECO:0000250|UniProtKB:P02760};
DE Contains:
DE RecName: Full=Inter-alpha-trypsin inhibitor light chain;
DE Short=ITI-LC;
DE AltName: Full=Bikunin;
DE AltName: Full=HI-30;
DE Contains:
DE RecName: Full=Trypstatin;
DE Flags: Precursor;
GN Name=AMBP; Synonyms=ITIL;
OS Meriones unguiculatus (Mongolian jird) (Gerbillus unguiculatus).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae;
OC Gerbillinae; Meriones.
OX NCBI_TaxID=10047;
RN [1]
RP NUCLEOTIDE SEQUENCE [MRNA].
RC TISSUE=Liver;
RX PubMed=7529051; DOI=10.1016/0167-4838(94)90198-8;
RA Ide H., Itoh H., Nawa Y.;
RT "Sequencing of cDNAs encoding alpha 1-microglobulin/bikunin of Mongolian
RT gerbil and Syrian golden hamster in comparison with man and other
RT species.";
RL Biochim. Biophys. Acta 1209:286-292(1994).
CC -!- FUNCTION: [Alpha-1-microglobulin]: Antioxidant and tissue repair
CC protein with reductase, heme-binding and radical-scavenging activities.
CC Removes and protects against harmful oxidants and repairs
CC macromolecules in intravascular and extravascular spaces and in
CC intracellular compartments. Intravascularly, plays a regulatory role in
CC red cell homeostasis by preventing heme- and reactive oxygen species-
CC induced cell damage. Binds and degrades free heme to protect fetal and
CC adult red blood cells from hemolysis. Reduces extracellular
CC methemoglobin, a Fe3+ (ferric) form of hemoglobin that cannot bind
CC oxygen, back to the Fe2+ (ferrous) form deoxyhemoglobin, which has
CC oxygen-carrying potential. Upon acute inflammation, inhibits oxidation
CC of low-density lipoprotein particles by MPO and limits vascular damage.
CC Extravascularly, protects from oxidation products formed on
CC extracellular matrix structures and cell membranes. Catalyzes the
CC reduction of carbonyl groups on oxidized collagen fibers and preserves
CC cellular and extracellular matrix ultrastructures. Importantly,
CC counteracts the oxidative damage at blood-placenta interface,
CC preventing leakage of free fetal hemoglobin into the maternal
CC circulation. Intracellularly, has a role in maintaining mitochondrial
CC redox homeostasis. Bound to complex I of the respiratory chain of
CC mitochondria, may scavenge free radicals and preserve mitochondrial ATP
CC synthesis. Protects renal tubule epithelial cells from heme-induced
CC oxidative damage to mitochondria. Reduces cytochrome c from Fe3+
CC (ferric) to the Fe2+ (ferrous) state through formation of superoxide
CC anion radicals in the presence of ascorbate or NADH/NADPH electron
CC donor cofactors, ascorbate being the preferred cofactor (By
CC similarity). Has a chaperone role in facilitating the correct folding
CC of bikunin in the endoplasmic reticulum compartment (By similarity).
CC {ECO:0000250|UniProtKB:P02760, ECO:0000250|UniProtKB:Q07456}.
CC -!- FUNCTION: [Inter-alpha-trypsin inhibitor light chain]: Kunitz-type
CC serine protease inhibitor and structural component of extracellular
CC matrix with a role in extracellular space remodeling and cell adhesion.
CC Among others, has antiprotease activity toward kallikrein, a protease
CC involved in airway inflammation; inhibits GZMK/granzyme, a granule-
CC stored serine protease involved in NK and T cell cytotoxic responses;
CC and inhibits PLG/plasmin, a protease required for activation of matrix
CC metalloproteinases. As part of I-alpha-I complex, provides for the
CC heavy chains to be transferred from I-alpha-I complex to hyaluronan in
CC the presence of TNFAIP6, in a dynamic process that releases free
CC bikunin and remodels extracellular matrix proteoglycan structures. Free
CC bikunin, but not its heavy chain-bound form, acts as potent protease
CC inhibitor in airway secretions (By similarity). Part of hyaluronan-rich
CC extracellular matrix that surrounds oocyte during cumulus oophorus
CC expansion, an indispensable process for proper ovulation (By
CC similarity). Also inhibits calcium oxalate crystallization (By
CC similarity). {ECO:0000250|UniProtKB:P02760,
CC ECO:0000250|UniProtKB:Q07456}.
CC -!- FUNCTION: [Trypstatin]: Kunitz-type serine protease inhibitor. Has high
CC catalytic efficiency for F10/blood coagulation factor Xa and may act as
CC an anticoagulant by inhibiting prothrombin activation. Inhibits trypsin
CC and mast cell CMA1/chymase and tryptase proteases.
CC {ECO:0000250|UniProtKB:Q64240}.
CC -!- SUBUNIT: [Alpha-1-microglobulin]: Monomer. Homodimer. In plasma, it
CC occurs as a monomer or dimer and in covalently-linked complexes with
CC immunoglobulin A (IgA), ALB/albumin and F2/prothrombin. Chromophore-
CC bound alpha-1-microglobulin interacts with the constant region of
CC immunoglobulin A. Chromophore-bound alpha-1-microglobulin interacts
CC with ALB with molar ratio 2:1 and 1:1; this interaction does not
CC prevent fatty acid binding to ALB. Interacts with F2/prothrombin (via
CC N-terminus) with molar ratio 2:1 and 1:1; this interaction does not
CC prevent the activation of prothrombin to thrombin. Interacts with
CC NDUFAB1, a subunit of mitochondrial complex I (By similarity).
CC Interacts with FN1 (By similarity). {ECO:0000250|UniProtKB:P02760,
CC ECO:0000250|UniProtKB:Q64240}.
CC -!- SUBUNIT: [Inter-alpha-trypsin inhibitor light chain]: I-alpha-I plasma
CC protease inhibitors are assembled from one or two heavy chains (HC) and
CC one light chain, bikunin. Inter-alpha-inhibitor (I-alpha-I) is composed
CC of ITIH1/HC1, ITIH2/HC2 and bikunin, and pre-alpha-inhibitor (P-alpha-
CC I) of ITIH3/HC3 and bikunin. Interacts with TNFAIP6 (via Link domain).
CC {ECO:0000250|UniProtKB:P02760}.
CC -!- SUBUNIT: [Trypstatin]: Monomer. Also occurs as a complex with tryptase
CC in mast cells. {ECO:0000250|UniProtKB:Q64240}.
CC -!- SUBCELLULAR LOCATION: [Alpha-1-microglobulin]: Secreted
CC {ECO:0000250|UniProtKB:P02760}. Endoplasmic reticulum
CC {ECO:0000250|UniProtKB:P02760}. Cytoplasm, cytosol
CC {ECO:0000250|UniProtKB:P02760}. Cell membrane
CC {ECO:0000250|UniProtKB:P02760}; Peripheral membrane protein
CC {ECO:0000250|UniProtKB:P02760}. Nucleus membrane
CC {ECO:0000250|UniProtKB:P02760}; Peripheral membrane protein
CC {ECO:0000250|UniProtKB:P02760}. Mitochondrion inner membrane
CC {ECO:0000250|UniProtKB:P02760}; Peripheral membrane protein
CC {ECO:0000250|UniProtKB:P02760}. Secreted, extracellular space,
CC extracellular matrix {ECO:0000250|UniProtKB:P02760}. Note=The cellular
CC uptake occurs via a non-endocytotic pathway and allows for localization
CC to various membrane structures. A specific binding to plasma membrane
CC suggests the presence of a cell receptor, yet to be identified.
CC Directly binds collagen fibers type I. {ECO:0000250|UniProtKB:P02760}.
CC -!- TISSUE SPECIFICITY: Expressed by the liver and secreted in plasma.
CC -!- DOMAIN: [Inter-alpha-trypsin inhibitor light chain]: The Kunitz domains
CC 1 and 2 serve as protease inhibitor domains.
CC {ECO:0000250|UniProtKB:P02760}.
CC -!- PTM: The precursor is proteolytically processed into separately
CC functioning proteins. {ECO:0000250|UniProtKB:P02760}.
CC -!- PTM: [Alpha-1-microglobulin]: 3-hydroxykynurenine, an oxidized
CC tryptophan metabolite that is common in biological fluids, reacts with
CC Cys-53, Lys-111, Lys-137, and Lys-149 to form heterogeneous polycyclic
CC chromophores including hydroxanthommatin. The reaction by alpha-1-
CC microglobulin is autocatalytic; the human protein forms chromophore
CC even when expressed in insect and bacterial cells. The chromophore can
CC react with accessible cysteines forming non-reducible thioether cross-
CC links with other molecules of alpha-1-microglobulin or with other
CC proteins such as Ig alpha-1 chain C region 'Cys-352'.
CC {ECO:0000250|UniProtKB:P02760}.
CC -!- PTM: [Inter-alpha-trypsin inhibitor light chain]: Heavy chains are
CC interlinked with bikunin via a chondroitin 4-sulfate bridge to the C-
CC terminal aspartate. {ECO:0000250|UniProtKB:P02760}.
CC -!- PTM: [Inter-alpha-trypsin inhibitor light chain]: Proteolytically
CC cleaved by PRSS3 at Kunitz domain 2. {ECO:0000250|UniProtKB:P02760}.
CC -!- SIMILARITY: In the N-terminal section; belongs to the calycin
CC superfamily. Lipocalin family. {ECO:0000305}.
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DR EMBL; D31813; BAA06600.1; -; mRNA.
DR AlphaFoldDB; Q62577; -.
DR SMR; Q62577; -.
DR MEROPS; I02.006; -.
DR PRIDE; Q62577; -.
DR GO; GO:0005829; C:cytosol; IEA:UniProtKB-SubCell.
DR GO; GO:0005783; C:endoplasmic reticulum; IEA:UniProtKB-SubCell.
DR GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR GO; GO:0005615; C:extracellular space; ISS:UniProtKB.
DR GO; GO:0031314; C:extrinsic component of mitochondrial inner membrane; ISS:UniProtKB.
DR GO; GO:0005743; C:mitochondrial inner membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0031965; C:nuclear membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0005886; C:plasma membrane; ISS:UniProtKB.
DR GO; GO:0016209; F:antioxidant activity; ISS:UniProtKB.
DR GO; GO:0035374; F:chondroitin sulfate binding; ISS:UniProtKB.
DR GO; GO:0098633; F:collagen fibril binding; ISS:UniProtKB.
DR GO; GO:0020037; F:heme binding; ISS:UniProtKB.
DR GO; GO:0019862; F:IgA binding; ISS:UniProtKB.
DR GO; GO:0016491; F:oxidoreductase activity; IEA:UniProtKB-KW.
DR GO; GO:0016653; F:oxidoreductase activity, acting on NAD(P)H, heme protein as acceptor; ISS:UniProtKB.
DR GO; GO:0042803; F:protein homodimerization activity; ISS:UniProtKB.
DR GO; GO:0004867; F:serine-type endopeptidase inhibitor activity; ISS:UniProtKB.
DR GO; GO:0098869; P:cellular oxidant detoxification; ISS:UniProtKB.
DR GO; GO:0034614; P:cellular response to reactive oxygen species; ISS:UniProtKB.
DR GO; GO:1903606; P:cytochrome c metabolic process; ISS:UniProtKB.
DR GO; GO:0020027; P:hemoglobin metabolic process; ISS:UniProtKB.
DR CDD; cd00109; KU; 2.
DR Gene3D; 2.40.128.20; -; 1.
DR Gene3D; 4.10.410.10; -; 2.
DR InterPro; IPR002968; A1-microglobln.
DR InterPro; IPR029856; AMBP.
DR InterPro; IPR012674; Calycin.
DR InterPro; IPR002223; Kunitz_BPTI.
DR InterPro; IPR036880; Kunitz_BPTI_sf.
DR InterPro; IPR000566; Lipocln_cytosolic_FA-bd_dom.
DR InterPro; IPR020901; Prtase_inh_Kunz-CS.
DR PANTHER; PTHR46676; PTHR46676; 1.
DR Pfam; PF00014; Kunitz_BPTI; 2.
DR Pfam; PF00061; Lipocalin; 1.
DR PRINTS; PR01215; A1MCGLOBULIN.
DR PRINTS; PR00759; BASICPTASE.
DR SMART; SM00131; KU; 2.
DR SUPFAM; SSF50814; SSF50814; 1.
DR SUPFAM; SSF57362; SSF57362; 2.
DR PROSITE; PS00280; BPTI_KUNITZ_1; 2.
DR PROSITE; PS50279; BPTI_KUNITZ_2; 2.
PE 2: Evidence at transcript level;
KW Cell membrane; Chromophore; Cleavage on pair of basic residues; Cytoplasm;
KW Disulfide bond; Endoplasmic reticulum; Extracellular matrix; Glycoprotein;
KW Membrane; Mitochondrion; Mitochondrion inner membrane; Nucleus;
KW Oxidoreductase; Protease inhibitor; Repeat; Secreted;
KW Serine protease inhibitor; Signal.
FT SIGNAL 1..19
FT /evidence="ECO:0000250"
FT CHAIN 20..202
FT /note="Alpha-1-microglobulin"
FT /id="PRO_0000017888"
FT CHAIN 205..346
FT /note="Inter-alpha-trypsin inhibitor light chain"
FT /id="PRO_0000017889"
FT CHAIN 283..343
FT /note="Trypstatin"
FT /evidence="ECO:0000250"
FT /id="PRO_0000318927"
FT DOMAIN 230..280
FT /note="BPTI/Kunitz inhibitor 1"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DOMAIN 286..336
FT /note="BPTI/Kunitz inhibitor 2"
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT BINDING 52
FT /ligand="3-hydroxy-L-kynurenine"
FT /ligand_id="ChEBI:CHEBI:58125"
FT /ligand_note="multimeric 3-hydroxykynurenine chromophore"
FT /note="covalent"
FT /evidence="ECO:0000250|UniProtKB:P02760"
FT BINDING 110
FT /ligand="3-hydroxy-L-kynurenine"
FT /ligand_id="ChEBI:CHEBI:58125"
FT /ligand_note="multimeric 3-hydroxykynurenine chromophore"
FT /note="covalent"
FT /evidence="ECO:0000250|UniProtKB:P02760"
FT BINDING 136
FT /ligand="3-hydroxy-L-kynurenine"
FT /ligand_id="ChEBI:CHEBI:58125"
FT /ligand_note="multimeric 3-hydroxykynurenine chromophore"
FT /note="covalent"
FT /evidence="ECO:0000250|UniProtKB:P02760"
FT BINDING 148
FT /ligand="3-hydroxy-L-kynurenine"
FT /ligand_id="ChEBI:CHEBI:58125"
FT /ligand_note="multimeric 3-hydroxykynurenine chromophore"
FT /note="covalent"
FT /evidence="ECO:0000250|UniProtKB:P02760"
FT SITE 240..241
FT /note="Inhibitory (P1) (chymotrypsin, elastase)"
FT /evidence="ECO:0000250"
FT SITE 296..297
FT /note="Inhibitory (P1) (trypsin)"
FT /evidence="ECO:0000250"
FT CARBOHYD 114
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 249
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT DISULFID 90..187
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DISULFID 230..280
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DISULFID 239..263
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DISULFID 255..276
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DISULFID 286..336
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DISULFID 295..319
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
FT DISULFID 311..332
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00031"
SQ SEQUENCE 346 AA; 38643 MW; F1A4463810918D5F CRC64;
MKGLGTLFLL LTACLASRAD DAATLPDIQV QENFIESLIY GKWFNLAVGS TCPWLRRIKD
KMSMSTLVLQ EGATEAEISM TSTRWRRGVC EEISGAYEKT DIDGKFLYHK SKWNITLETY
VVHTNYDEYA IFLTKKFSHY HGPTITLKLY GREPKLRDSL LLEFREVALS MGIPENSIVF
MADKGECVPG DQEVKPSPHL RARRAVLPQE NEGSGSEPLV TGILKKEDSC QLTYSEGPCL
GMMERYHYNG TSMACETFQY GGCLGNGNNF ISEKECLQTC RTVAACNLPI VQGPCRAYIK
LWAFDAAQGK CIQFTYGGCK GNGNKFYSEK ECKEYCGVPG DGDKTN
