ID   IL2_DELLE               Reviewed;         154 AA.
AC   Q9XT84;
DT   12-APR-2005, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1999, sequence version 1.
DT   03-AUG-2022, entry version 83.
DE   RecName: Full=Interleukin-2;
DE            Short=IL-2;
DE   AltName: Full=T-cell growth factor;
DE            Short=TCGF;
DE   Flags: Precursor;
GN   Name=IL2;
OS   Delphinapterus leucas (Beluga whale).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Eutheria; Laurasiatheria; Artiodactyla; Whippomorpha; Cetacea; Odontoceti;
OC   Monodontidae; Delphinapterus.
OX   NCBI_TaxID=9749;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA].
RX   PubMed=10206205; DOI=10.1016/s0165-2427(99)00009-4;
RA   St Laurent G., Beliveau C., Archambault D.;
RT   "Molecular cloning and phylogenetic analysis of beluga whale
RT   (Delphinapterus leucas) and grey seal (Halichoerus grypus) interleukin 2.";
RL   Vet. Immunol. Immunopathol. 67:385-394(1999).
CC   -!- FUNCTION: Cytokine produced by activated CD4-positive helper T-cells
CC       and to a lesser extend activated CD8-positive T-cells and natural
CC       killer (NK) cells that plays pivotal roles in the immune response and
CC       tolerance. Binds to a receptor complex composed of either the high-
CC       affinity trimeric IL-2R (IL2RA/CD25, IL2RB/CD122 and IL2RG/CD132) or
CC       the low-affinity dimeric IL-2R (IL2RB and IL2RG). Interaction with the
CC       receptor leads to oligomerization and conformation changes in the IL-2R
CC       subunits resulting in downstream signaling starting with
CC       phosphorylation of JAK1 and JAK3. In turn, JAK1 and JAK3 phosphorylate
CC       the receptor to form a docking site leading to the phosphorylation of
CC       several substrates including STAT5. This process leads to activation of
CC       several pathways including STAT, phosphoinositide-3-kinase/PI3K and
CC       mitogen-activated protein kinase/MAPK pathways. Functions as a T-cell
CC       growth factor and can increase NK-cell cytolytic activity as well.
CC       Promotes strong proliferation of activated B-cells and subsequently
CC       immunoglobulin production. Plays a pivotal role in regulating the
CC       adaptive immune system by controlling the survival and proliferation of
CC       regulatory T-cells, which are required for the maintenance of immune
CC       tolerance. Moreover, participates in the differentiation and
CC       homeostasis of effector T-cell subsets, including Th1, Th2, Th17 as
CC       well as memory CD8-positive T-cells. {ECO:0000250|UniProtKB:P60568}.
CC   -!- SUBCELLULAR LOCATION: Secreted {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the IL-2 family. {ECO:0000305}.
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DR   EMBL; AF072870; AAD40847.1; -; mRNA.
DR   AlphaFoldDB; Q9XT84; -.
DR   SMR; Q9XT84; -.
DR   STRING; 9749.Q9XT84; -.
DR   Proteomes; UP000248483; Unplaced.
DR   GO; GO:0005615; C:extracellular space; IEA:UniProtKB-KW.
DR   GO; GO:0005125; F:cytokine activity; IEA:UniProtKB-KW.
DR   GO; GO:0008083; F:growth factor activity; IEA:UniProtKB-KW.
DR   GO; GO:0005134; F:interleukin-2 receptor binding; IEA:InterPro.
DR   GO; GO:0002250; P:adaptive immune response; IEA:UniProtKB-KW.
DR   Gene3D; 1.20.1250.10; -; 1.
DR   InterPro; IPR009079; 4_helix_cytokine-like_core.
DR   InterPro; IPR000779; IL-2.
DR   InterPro; IPR030477; IL-2_CS.
DR   Pfam; PF00715; IL2; 1.
DR   PRINTS; PR00265; INTERLEUKIN2.
DR   SMART; SM00189; IL2; 1.
DR   SUPFAM; SSF47266; SSF47266; 1.
DR   PROSITE; PS00424; INTERLEUKIN_2; 1.
PE   2: Evidence at transcript level;
KW   Adaptive immunity; Cytokine; Disulfide bond; Glycoprotein; Growth factor;
KW   Immunity; Reference proteome; Secreted; Signal.
FT   SIGNAL          1..20
FT                   /evidence="ECO:0000250"
FT   CHAIN           21..154
FT                   /note="Interleukin-2"
FT                   /id="PRO_0000015480"
FT   CARBOHYD        23
FT                   /note="O-linked (GalNAc...) threonine"
FT                   /evidence="ECO:0000250"
FT   DISULFID        78..126
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   154 AA;  17653 MW;  4288D3D41D04F172 CRC64;
     MYKMQLLSCI ALTLALVANG APTSSSTENT KKQVQSLLQD LHLLLKEINN HENLKLFRML
     AFKFYMPKKA TELKHLQCLA EELKPLEDVL NVAQSKTQNS IDIKDLMDNI NRIVLTLKGS
     ETRFTCEYDD ETVTAVEFLN KWITFCQSIY STMT