ID   B4_USTMD                Reviewed;         410 AA.
AC   P22018;
DT   01-AUG-1991, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1991, sequence version 1.
DT   25-MAY-2022, entry version 83.
DE   RecName: Full=Mating-type locus allele B4 protein;
OS   Ustilago maydis (Corn smut fungus).
OC   Eukaryota; Fungi; Dikarya; Basidiomycota; Ustilaginomycotina;
OC   Ustilaginomycetes; Ustilaginales; Ustilaginaceae; Ustilago.
OX   NCBI_TaxID=5270;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=RK138;
RX   PubMed=1967554; DOI=10.1016/0092-8674(90)90744-y;
RA   Schulz B., Banuett F., Dahl M., Schlesinger R., Schaefer W., Martin T.,
RA   Herskowitz I., Kahmann R.;
RT   "The b alleles of U. maydis, whose combinations program pathogenic
RT   development, code for polypeptides containing a homeodomain-related
RT   motif.";
RL   Cell 60:295-306(1990).
CC   -!- FUNCTION: The B locus has at least 25 alleles, and any combination of
CC       two different B alleles yields a multimeric regulatory protein, that
CC       activates genes responsible for the pathogenicity and for the sexual
CC       development of the fungus within the corn plant.
CC   -!- SUBCELLULAR LOCATION: Nucleus.
CC   -!- SIMILARITY: Belongs to the TALE/M-ATYP homeobox family. {ECO:0000305}.
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DR   EMBL; M58556; AAA63556.1; -; Genomic_DNA.
DR   PIR; C32696; C32696.
DR   AlphaFoldDB; P22018; -.
DR   SMR; P22018; -.
DR   PRIDE; P22018; -.
DR   VEuPathDB; FungiDB:UMAG_12052; -.
DR   GO; GO:0005634; C:nucleus; IEA:UniProtKB-SubCell.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0006355; P:regulation of transcription, DNA-templated; IEA:InterPro.
DR   CDD; cd00086; homeodomain; 1.
DR   InterPro; IPR009057; Homeobox-like_sf.
DR   InterPro; IPR001356; Homeobox_dom.
DR   InterPro; IPR008422; Homeobox_KN_domain.
DR   InterPro; IPR008888; Ustilago_mating.
DR   Pfam; PF05920; Homeobox_KN; 1.
DR   Pfam; PF05722; Ustilago_mating; 1.
DR   SUPFAM; SSF46689; SSF46689; 1.
DR   PROSITE; PS50071; HOMEOBOX_2; 1.
PE   3: Inferred from homology;
KW   DNA-binding; Homeobox; Nucleus.
FT   CHAIN           1..410
FT                   /note="Mating-type locus allele B4 protein"
FT                   /id="PRO_0000049404"
FT   DNA_BIND        107..184
FT                   /note="Homeobox; TALE-type"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00108"
FT   REGION          1..110
FT                   /note="Variable domain between B alleles"
FT   REGION          111..410
FT                   /note="Highly conserved between B alleles"
FT   REGION          202..241
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          278..335
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          333..410
FT                   /note="Not essential for B4 function"
FT   REGION          375..394
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   MOTIF           276..308
FT                   /note="Nuclear localization signal"
FT                   /evidence="ECO:0000255"
FT   COMPBIAS        202..229
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        309..335
FT                   /note="Polar residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ   SEQUENCE   410 AA;  46061 MW;  D4B1C36E5C702291 CRC64;
     MSSDPKISIT SFLECLSEIE EEFLRDKEKN PPVLVSKLQE LQQKTPNNIA NLDHDPETIQ
     KIHQTTHRIN VAVKAFICID QTFVSLRSDA VEDASRALKK ANASSPVVGC RELSEDLPAY
     HMRKHFLHTL ENPYPTQEEK ETLVRLTNES TARVGQSIVN RPPLEVHQLT LWFINARRRS
     GWSHILKKFA REDRSRMKHL VRAKLSSSNQ STPPSPTSEY PSNNLDDFLS DNLGRPLTPA
     DKQQFEDDWA SMISWIKYGV KEKVGDWVYD LCAASKKTPK PGMPRPVTTV AKRQPARKTK
     PAAKPKSRTA NPRASTTPSI DSTLDSSKLE STPELSMCST ADTSFSTFGS SLSMSHYDPF
     QYGNDILQSP TFKARGNRKV KALPKRAGKQ QPDEVENGKI PFLCLSVAFV