Speckle targeted PIP5K1A-regulated poly(A) polymerase (Star-PAP) (EC 2.7.7.19) (RNA-binding motif protein 21) (RNA-binding protein 21) (U6 snRNA-specific terminal uridylyltransferase 1) (U6-TUTase) (EC 2.7.7.52)
1_MAAVD 6_ SDVES 11_ LPRGG 16_ FRCCL 21_ CHVTT 26_ ANRPS 31_ LDAHL 36_ GGRKH 41_ RHLVE 46_ LRAAR 51_ KAQGL 56_ RSVFV 61_ SGFPR 66_ DVDSA 71_ QLSEY 76_ FLAFG 81_ PVASV 86_ VMDKD 91_ KGVFA 96_ IVEMG 101_ DVGAR 106_ EAVLS 111_ QSQHS 116_ LGGHR 121_ LRVRP 126_ REQKE 131_ FQSPA 136_ SKSPK 141_ GAAPD 146_ SHQLA 151_ KALAE 156_ AADVG 161_ AQMIK 166_ LVGLR 171_ ELSEA 176_ ERQLR 181_ SLVVA 186_ LMQEV 191_ FTEFF 196_ PGCVV 201_ HPFGS 206_ SINSF 211_ DVHGC 216_ DLDLF 221_ LDLGD 226_ LEEPQ 231_ PVPKA 236_ PESPS 241_ LDSAL 246_ ASPLD 251_ PQALA 256_ CTPAS 261_ PPDSQ 266_ PPASP 271_ QDSEA 276_ LDFET 281_ PSSSL 286_ APQTP 291_ DSALA 296_ SETLA 301_ SPQSL 306_ PPASP 311_ LLEDR 316_ EEGDL 321_ GKASE 326_ LAETP 331_ KEEKA 336_ EGAAM 341_ LELVG 346_ SILRG 351_ CVPGV 356_ YRVQT 361_ VPSAR 366_ RPVVK 371_ FCHRP 376_ SGLHG 381_ DVSLS 386_ NRLAL 391_ HNSRF 396_ LSLCS 401_ ELDGR 406_ VRPLV 411_ YTLRC 416_ WAQGR 421_ GLSGS 426_ GPLLS 431_ NYALT 436_ LLVIY 441_ FLQTR 446_ DPPVL 451_ PTVSQ 456_ LTQKA 461_ GEGEQ 466_ VEVDG 471_ WDCSF 476_ PRDAS 481_ RLEPS 486_ INVEP 491_ LSSLL 496_ AQFFS 501_ CVSCW 506_ DLRGS 511_ LLSLR 516_ EGQAL 521_ PVAGG 526_ LPSNL 531_ WEGLR 536_ LGPLN 541_ LQDPF 546_ DLSHN 551_ VAANV 556_ TSRVA 561_ GRLQN 566_ CCRAA 571_ ANYCR 576_ SLQYQ 581_ RRSSR 586_ GRDWG 591_ LLPLL 596_ QPSSP 601_ SSLLS 606_ ATPIP 611_ LPLAP 616_ FTQLT 621_ AALVQ 626_ VFREA 631_ LGCHI 636_ EQATK 641_ RTRSE 646_ GGGTG 651_ ESSQG 656_ GTSKR 661_ LKVDG 666_ QKNCC 671_ EEGKE 676_ EQQGC 681_ AGDGG 686_ EDRVE 691_ EMVIE 696_ VGEMV 701_ QDWAM 706_ QSPGQ 711_ PGDLP 716_ LTTGK 721_ HGAPG 726_ EEGQP 731_ SHAAL 736_ AERGP 741_ KGHEA 746_ AQEWS 751_ QGEAG 756_ KGASL 761_ PSSAS 766_ WRCAL 771_ WHRVW 776_ QGRRR 781_ ARRRL 786_ QQQTK 791_ EGAGG 796_ GAGTR 801_ AGWLA 806_ TEAQV 811_ TQELK 816_ GLSGG 821_ EERPE 826_ TEPLL 831_ SFVAS 836_ VSPAD 841_ RMLTV 846_ TPLQD 851_ PQGLF 856_ PDLHH 861_ FLQVF 866_LPQAI
1: Poly(A) polymerase that creates the 3'-poly(A) tail of specific pre-mRNAs (PubMed:18288197, PubMed:21102410). Localizes to nuclear speckles together with PIP5K1A and mediates polyadenylation of a select set of mRNAs, such as HMOX1 (PubMed:18288197). In addition to polyadenylation, it is also required for the 3'-end cleavage of pre-mRNAs: binds to the 3'UTR of targeted pre-mRNAs and promotes the recruitment and assembly of the CPSF complex on the 3'UTR of pre-mRNAs (PubMed:21102410). In addition to adenylyltransferase activity, also has uridylyltransferase activity (PubMed:16790842, PubMed:18288197, PubMed:28589955). However, the ATP ratio is higher than UTP in cells, suggesting that it functions primarily as a poly(A) polymerase (PubMed:18288197). Acts as a specific terminal uridylyltransferase for U6 snRNA in vitro: responsible for a controlled elongation reaction that results in the restoration of the four 3'-terminal UMP-residues found in newly transcribed U6 snRNA (PubMed:16790842, PubMed:18288197, PubMed:28589955). Not involved in replication-dependent histone mRNA degradation