Nuclear cap-binding protein subunit 1 (80 kDa nuclear cap-binding protein) (CBP80) (NCBP 80 kDa subunit)
1_MSRRR 6_ HSDEN 11_ DGGQP 16_ HKRRK 21_ TSDAN 26_ ETEDH 31_ LESLI 36_ CKVGE 41_ KSACS 46_ LESNL 51_ EGLAG 56_ VLEAD 61_ LPNYK 66_ SKILR 71_ LLCTV 76_ ARLLP 81_ EKLTI 86_ YTTLV 91_ GLLNA 96_ RNYNF 101_ GGEFV 106_ EAMIR 111_ QLKES 116_ LKANN 121_ YNEAV 126_ YLVRF 131_ LSDLV 136_ NCHVI 141_ AAPSM 146_ VAMFE 151_ NFVSV 156_ TQEED 161_ VPQVR 166_ RDWYV 171_ YAFLS 176_ SLPWV 181_ GKELY 186_ EKKDA 191_ EMDRI 196_ FANTE 201_ SYLKR 206_ RQKTH 211_ VPMLQ 216_ VWTAD 221_ KPHPQ 226_ EEYLD 231_ CLWAQ 236_ IQKLK 241_ KDRWQ 246_ ERHIL 251_ RPYLA 256_ FDSIL 261_ CEALQ 266_ HNLPP 271_ FTPPP 276_ HTEDS 281_ VYPMP 286_ RVIFR 291_ MFDYT 296_ DDPEG 301_ PVMPG 306_ SHSVE 311_ RFVIE 316_ ENLHC 321_ IIKSH 326_ WKERK 331_ TCAAQ 336_ LVSYP 341_ GKNKI 346_ PLNYH 351_ IVEVI 356_ FAELF 361_ QLPAP 366_ PHIDV 371_ MYTTL 376_ LIELC 381_ KLQPG 386_ SLPQV 391_ LAQAT 396_ EMLYM 401_ RLDTM 406_ NTTCV 411_ DRFIN 416_ WFSHH 421_ LSNFQ 426_ FRWSW 431_ EDWSD 436_ CLSQD 441_ PESPK 446_ PKFVR 451_ EVLEK 456_ CMRLS 461_ YHQRI 466_ LDIVP 471_ PTFSA 476_ LCPAN 481_ PTCIY 486_ KYGDE 491_ SSNSL 496_ PGHSV 501_ ALCLA 506_ VAFKS 511_ KATND 516_ EIFSI 521_ LKDVP 526_ NPNQD 531_ DDDDE 536_ GFSFN 541_ PLKIE 546_ VFVQT 551_ LLHLA 556_ AKSFS 561_ HSFSA 566_ LAKFH 571_ EVFKT 576_ LAESD 581_ EGKLH 586_ VLRVM 591_ FEVWR 596_ NHPQM 601_ IAVLV 606_ DKMIR 611_ TQIVD 616_ CAAVA 621_ NWIFS 626_ SELSR 631_ DFTRL 636_ FVWEI 641_ LHSTI 646_ RKMNK 651_ HVLKI 656_ QKELE 661_ EAKEK 666_ LARQH 671_ KRRSD 676_ DDDRS 681_ SDRKD 686_ GVLEE 691_ QIERL 696_ QEKVE 701_ SAQSE 706_ QKNLF 711_ LVIFQ 716_ RFIMI 721_ LTEHL 726_ VRCET 731_ DGTSV 736_ LTPWY 741_ KNCIE 746_ RLQQI 751_ FLQHH 756_ QIIQQ 761_ YMVTL 766_ ENLLF 771_ TAELD 776_ PHILA 781_VFQQF
1: Component of the cap-binding complex (CBC), which binds cotranscriptionally to the 5'-cap of pre-mRNAs and is involved in various processes such as pre-mRNA splicing, translation regulation, nonsense-mediated mRNA decay, RNA-mediated gene silencing (RNAi) by microRNAs (miRNAs) and mRNA export. The CBC complex is involved in mRNA export from the nucleus via its interaction with ALYREF/THOC4/ALY, leading to the recruitment of the mRNA export machinery to the 5'-end of mRNA and to mRNA export in a 5' to 3' direction through the nuclear pore. The CBC complex is also involved in mediating U snRNA and intronless mRNAs export from the nucleus. The CBC complex is essential for a pioneer round of mRNA translation, before steady state translation when the CBC complex is replaced by cytoplasmic cap-binding protein eIF4E. The pioneer round of mRNA translation mediated by the CBC complex plays a central role in nonsense-mediated mRNA decay (NMD), NMD only taking place in mRNAs bound to the CBC complex, but not on eIF4E-bound mRNAs. The CBC complex enhances NMD in mRNAs containing at least one exon-junction complex (EJC) via its interaction with UPF1, promoting the interaction between UPF1 and UPF2. The CBC complex is also involved in 'failsafe' NMD, which is independent of the EJC complex, while it does not participate in Staufen-mediated mRNA decay (SMD). During cell proliferation, the CBC complex is also involved in microRNAs (miRNAs) biogenesis via its interaction with SRRT/ARS2 and is required for miRNA-mediated RNA interference. The CBC complex also acts as a negative regulator of PARN, thereby acting as an inhibitor of mRNA deadenylation. In the CBC complex, NCBP1/CBP80 does not bind directly capped RNAs (m7GpppG-capped RNA) but is required to stabilize the movement of the N-terminal loop of NCBP2/CBP20 and lock the CBC into a high affinity cap-binding state with the cap structure. Associates with NCBP3 to form an alternative cap-binding complex (CBC) which plays a key role in mRNA export and is particularly important in cellular stress situations such as virus infections. The conventional CBC with NCBP2 binds both small nuclear RNA (snRNA) and messenger (mRNA) and is involved in their export from the nucleus whereas the alternative CBC with NCBP3 does not bind snRNA and associates only with mRNA thereby playing a role only in mRNA export. NCBP1/CBP80 is required for cell growth and viability (PubMed:26382858)