ID   MUCM_ICTPU              Reviewed;         380 AA.
AC   P23735;
DT   01-NOV-1991, integrated into UniProtKB/Swiss-Prot.
DT   04-FEB-2015, sequence version 2.
DT   25-MAY-2022, entry version 94.
DE   RecName: Full=Ig mu chain C region membrane-bound form;
OS   Ictalurus punctatus (Channel catfish) (Silurus punctatus).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Actinopterygii; Neopterygii; Teleostei; Ostariophysi; Siluriformes;
OC   Ictaluridae; Ictalurus.
OX   NCBI_TaxID=7998;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA] (ISOFORMS 1 AND 2), NUCLEOTIDE SEQUENCE [GENOMIC
RP   DNA], SUBCELLULAR LOCATION (ISOFORMS 1 AND 2), AND TISSUE SPECIFICITY
RP   (ISOFORMS 1 AND 2).
RC   TISSUE=Lymphocyte;
RX   PubMed=2119496; DOI=10.1093/nar/18.17.5227;
RA   Wilson M.R., Marcuz A., van Ginkel F., Miller N.W., Clem L.W.,
RA   Middleton D., Warr G.W.;
RT   "The immunoglobulin M heavy chain constant region gene of the channel
RT   catfish, Ictalurus punctatus: an unusual mRNA splice pattern produces the
RT   membrane form of the molecule.";
RL   Nucleic Acids Res. 18:5227-5233(1990).
CC   -!- SUBCELLULAR LOCATION: [Isoform 1]: Cell membrane
CC       {ECO:0000269|PubMed:2119496}; Single-pass membrane protein
CC       {ECO:0000305}.
CC   -!- SUBCELLULAR LOCATION: [Isoform 2]: Secreted
CC       {ECO:0000269|PubMed:2119496}.
CC   -!- ALTERNATIVE PRODUCTS:
CC       Event=Alternative splicing; Named isoforms=2;
CC       Name=1; Synonyms=Membrane-bound {ECO:0000303|PubMed:2119496};
CC         IsoId=P23735-1; Sequence=Displayed;
CC       Name=2; Synonyms=Secreted {ECO:0000303|PubMed:2119496};
CC         IsoId=P23735-2; Sequence=VSP_057465;
CC   -!- TISSUE SPECIFICITY: Isoform 1 and isoform 2 are expressed in leukocytes
CC       (PubMed:2119496). {ECO:0000269|PubMed:2119496}.
CC   -!- MISCELLANEOUS: During differentiation, B-lymphocytes switch from
CC       expression of membrane-bound IgM to secretion of IgM. The mu chains of
CC       membrane and secreted IgM differ in their C-terminal segments.
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DR   EMBL; X52617; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR   AlphaFoldDB; P23735; -.
DR   SMR; P23735; -.
DR   STRING; 7998.ENSIPUP00000000238; -.
DR   Proteomes; UP000221080; Genome assembly.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
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:0034987; F:immunoglobulin receptor binding; IPI:AgBase.
DR   Gene3D; 2.60.40.10; -; 3.
DR   InterPro; IPR007110; Ig-like_dom.
DR   InterPro; IPR036179; Ig-like_dom_sf.
DR   InterPro; IPR013783; Ig-like_fold.
DR   InterPro; IPR003006; Ig/MHC_CS.
DR   InterPro; IPR003597; Ig_C1-set.
DR   Pfam; PF07654; C1-set; 3.
DR   SMART; SM00407; IGc1; 2.
DR   SUPFAM; SSF48726; SSF48726; 3.
DR   PROSITE; PS50835; IG_LIKE; 2.
DR   PROSITE; PS00290; IG_MHC; 1.
PE   2: Evidence at transcript level;
KW   Alternative splicing; Cell membrane; Disulfide bond; Glycoprotein;
KW   Immunoglobulin domain; Membrane; Secreted; Transmembrane;
KW   Transmembrane helix.
FT   CHAIN           <1..380
FT                   /note="Ig mu chain C region membrane-bound form"
FT                   /id="PRO_0000153628"
FT   TRANSMEM        357..377
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TOPO_DOM        378..380
FT                   /note="Cytoplasmic"
FT                   /evidence="ECO:0000255"
FT   REGION          5..103
FT                   /note="CH1"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   REGION          108..204
FT                   /note="CH2"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   REGION          209..309
FT                   /note="CH3"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   CARBOHYD        122
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        165
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        258
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   CARBOHYD        319
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255"
FT   DISULFID        14
FT                   /note="Interchain (with a light chain)"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   DISULFID        26..85
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   DISULFID        129..188
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   DISULFID        228..290
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00114"
FT   VAR_SEQ         334..380
FT                   /note="Missing (in isoform 2)"
FT                   /id="VSP_057465"
FT   NON_TER         1
SQ   SEQUENCE   380 AA;  41981 MW;  7124312EB1448A82 CRC64;
     VQSAPKSLFP VWQCGSASDG LVTLGCVTRD LASADGLSFI WKDASGSALT DVVQYPAVQA
     TGGYTSVSHV RVKASDWNGN KKFTCEVKNG LGSKDASLQK PVERELHASL LLTTPTQTEI
     DNGTATFVCL ATPFSPKSHT FKWTLEKTDI SNKVKENIVS QNKGNFTAIS VLELSASEWT
     SSTSPVKCEF QQKNHNVFKE ASYGNPEFPK VYLLAPPESS GESVTLTCYV KDFYPKEVAV
     SWLVNDKQVE EVVGYEQNTT AVIDRNNLFS VYSQLIIKTA DWNSGSVFSC LVYHESIKDC
     VRHISRSIAK DSKTPTLVNL TLTNPQSCSC STYVCIWSTE IFHYEMEMDD DNMANTALTF
     VFLFLITLFY SIGVTVFKVK