CD4_DELLE
ID CD4_DELLE Reviewed; 455 AA.
AC Q9XS78;
DT 20-DEC-2005, integrated into UniProtKB/Swiss-Prot.
DT 01-NOV-1999, sequence version 1.
DT 03-AUG-2022, entry version 86.
DE RecName: Full=T-cell surface glycoprotein CD4;
DE AltName: Full=T-cell surface antigen T4/Leu-3;
DE AltName: CD_antigen=CD4;
DE Flags: Precursor;
GN Name=CD4;
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].
RC TISSUE=Thymus;
RX PubMed=10199913; DOI=10.1007/s002510050510;
RA Romano T.A., Ridgway S.H., Felten D.L., Quaranta V.;
RT "Molecular cloning and characterization of CD4 in an aquatic mammal, the
RT white whale Delphinapterus leucas.";
RL Immunogenetics 49:376-383(1999).
CC -!- FUNCTION: Integral membrane glycoprotein that plays an essential role
CC in the immune response and serves multiple functions in responses
CC against both external and internal offenses. In T-cells, functions
CC primarily as a coreceptor for MHC class II molecule:peptide complex.
CC The antigens presented by class II peptides are derived from
CC extracellular proteins while class I peptides are derived from
CC cytosolic proteins. Interacts simultaneously with the T-cell receptor
CC (TCR) and the MHC class II presented by antigen presenting cells
CC (APCs). In turn, recruits the Src kinase LCK to the vicinity of the
CC TCR-CD3 complex. LCK then initiates different intracellular signaling
CC pathways by phosphorylating various substrates ultimately leading to
CC lymphokine production, motility, adhesion and activation of T-helper
CC cells. In other cells such as macrophages or NK cells, plays a role in
CC differentiation/activation, cytokine expression and cell migration in a
CC TCR/LCK-independent pathway. Participates in the development of T-
CC helper cells in the thymus and triggers the differentiation of
CC monocytes into functional mature macrophages.
CC {ECO:0000250|UniProtKB:P01730}.
CC -!- SUBUNIT: Forms disulfide-linked homodimers at the cell surface.
CC Interacts with LCK. Interacts with PTK2/FAK1. Binds to P4HB/PDI.
CC Interacts with IL16; this interaction induces a CD4-dependent signaling
CC in lymphocytes. Interacts (via Ig-like V-type domain) with MHCII alpha
CC chain (via alpha-2 domain) and beta chain (via beta-2 domain); this
CC interaction increases the affinity of TCR for peptide-MHCII. CD4
CC oligomerization via Ig-like C2-type 2 and 3 domains appears to be
CC required for stable binding to MHCII and adhesion between T cells and
CC APCs. {ECO:0000250|UniProtKB:P01730}.
CC -!- SUBCELLULAR LOCATION: Cell membrane {ECO:0000250|UniProtKB:P01730};
CC Single-pass type I membrane protein {ECO:0000250|UniProtKB:P01730}.
CC Note=Localizes to lipid rafts. {ECO:0000250|UniProtKB:P01730}.
CC -!- DOMAIN: The Ig-like V-type domain mediates the interaction with MHCII.
CC {ECO:0000250|UniProtKB:P01730}.
CC -!- PTM: Palmitoylation and association with LCK contribute to the
CC enrichment of CD4 in lipid rafts. {ECO:0000250|UniProtKB:P01730}.
CC -!- PTM: Phosphorylated by PKC; phosphorylation plays an important role for
CC CD4 internalization. {ECO:0000250|UniProtKB:P01730}.
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DR EMBL; AF071799; AAD23738.1; -; mRNA.
DR AlphaFoldDB; Q9XS78; -.
DR SMR; Q9XS78; -.
DR STRING; 9749.Q9XS78; -.
DR Ensembl; ENSDLET00000023397; ENSDLEP00000021247; ENSDLEG00000015440.
DR OrthoDB; 652984at2759; -.
DR Proteomes; UP000248483; Unplaced.
DR GO; GO:0009986; C:cell surface; IEA:UniProt.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0015026; F:coreceptor activity; IEA:InterPro.
DR GO; GO:0023026; F:MHC class II protein complex binding; ISS:UniProtKB.
DR GO; GO:0002250; P:adaptive immune response; IEA:UniProtKB-KW.
DR GO; GO:0007155; P:cell adhesion; IEA:InterPro.
DR Gene3D; 2.60.40.10; -; 4.
DR InterPro; IPR000973; CD4.
DR InterPro; IPR015274; CD4-extracel.
DR InterPro; IPR007110; Ig-like_dom.
DR InterPro; IPR036179; Ig-like_dom_sf.
DR InterPro; IPR013783; Ig-like_fold.
DR InterPro; IPR008424; Ig_C2-set.
DR InterPro; IPR003599; Ig_sub.
DR InterPro; IPR013106; Ig_V-set.
DR InterPro; IPR013151; Immunoglobulin.
DR InterPro; IPR021963; Tcell_CD4_Cterm.
DR PANTHER; PTHR11422:SF0; PTHR11422:SF0; 1.
DR Pfam; PF05790; C2-set; 2.
DR Pfam; PF09191; CD4-extracel; 1.
DR Pfam; PF00047; ig; 1.
DR Pfam; PF12104; Tcell_CD4_C; 1.
DR PRINTS; PR00692; CD4TCANTIGEN.
DR SMART; SM00409; IG; 3.
DR SMART; SM00406; IGv; 1.
DR SUPFAM; SSF48726; SSF48726; 4.
DR PROSITE; PS50835; IG_LIKE; 2.
PE 2: Evidence at transcript level;
KW Adaptive immunity; Cell membrane; Disulfide bond; Glycoprotein; Immunity;
KW Immunoglobulin domain; Lipoprotein; Membrane; Palmitate; Phosphoprotein;
KW Reference proteome; Repeat; Signal; Transmembrane; Transmembrane helix.
FT SIGNAL 1..25
FT /evidence="ECO:0000255"
FT CHAIN 26..455
FT /note="T-cell surface glycoprotein CD4"
FT /id="PRO_0000045165"
FT TOPO_DOM 26..394
FT /note="Extracellular"
FT /evidence="ECO:0000255"
FT TRANSMEM 395..415
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TOPO_DOM 416..455
FT /note="Cytoplasmic"
FT /evidence="ECO:0000255"
FT DOMAIN 26..125
FT /note="Ig-like V-type"
FT DOMAIN 126..203
FT /note="Ig-like C2-type 1"
FT DOMAIN 204..314
FT /note="Ig-like C2-type 2"
FT DOMAIN 315..371
FT /note="Ig-like C2-type 3"
FT REGION 145..165
FT /note="Disordered"
FT /evidence="ECO:0000256|SAM:MobiDB-lite"
FT MOD_RES 430
FT /note="Phosphoserine"
FT /evidence="ECO:0000250|UniProtKB:P01730"
FT MOD_RES 437
FT /note="Phosphoserine"
FT /evidence="ECO:0000250|UniProtKB:P01730"
FT MOD_RES 453
FT /note="Phosphoserine"
FT /evidence="ECO:0000250|UniProtKB:P01730"
FT LIPID 419
FT /note="S-palmitoyl cysteine"
FT /evidence="ECO:0000250"
FT CARBOHYD 46
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 220
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 231
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 295
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 299
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 343
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT DISULFID 41..109
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT DISULFID 325..367
FT /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
SQ SEQUENCE 455 AA; 50499 MW; AA532FD4411AA5D1 CRC64;
MDPRTSLRHL FLVLQLVMLP AGTQGKKVVL GKAGELAELP CKASQNKSLF FSWKNSYQTK
ILGRHGYFWH KGASNLHSRV ESKINLWDQG SFPLVIKDLE VPDSGTYICE VEDKKIEVEL
QVFRLTASSD TRLLLGQSLT LTLEGPSGSN PSVQWKGPGN KRKNEAKSLS LPQVGLQDSG
TWTCTVSQAQ QTLVFNKHIL VLAFQEVSST VYAKEGEQMN FSFPLTFGDE NLSGELSWLQ
AKGNSSPESW ITFKLNNGKV TVGKARKDLK LRMSKALPLH LTLPQALPQY AGSGNLTLNL
TKGKLYQEVN LVVMRVTKSP NSLTCEVLGP TSPRLILSLK KENQSMRVSD QQKLVTVLGP
EAGMWQCLLS DKGKVLLESK VKILPPVLAH AWPKLLAVVL GGITSLLLLA GFCIFSAKCW
HRRRRAERTS QIKRLLSEKK TCHCSHRLQK TCSLT
