. "FUNCTION: General coactivator that functions cooperatively with TAFs and mediates functional interactions between upstream activators and the general transcriptional machinery. May be involved in stabilizing the multiprotein transcription complex. Binds single-stranded DNA. Also binds, in vitro, non-specifically to double-stranded DNA (ds DNA). SUBUNIT: Homodimer. Interacts with CSTF2. SUBCELLULAR LOCATION: Nucleus. PTM: Activity is controlled by protein kinases that target the regulatory region. Phosphorylation inactivates both ds DNA-binding and cofactor function, but does not affect binding to ssDNA. Seems to be phosphorylated in vivo by CK2 in at least 7 sites in the N- terminal Ser-rich region. MASS SPECTROMETRY: Mass=14266; Mass_error=4; Method=MALDI; Range=2-127; Source=PubMed:7809103; MASS SPECTROMETRY: Mass=14263; Method=Electrospray; Range=2-127; Source=PubMed:16689930; SIMILARITY: Belongs to the transcriptional coactivator PC4 family. GENE SYNONYMS:SUB1 PC4 RPO2TC1. COPYRIGHT: Protein annotation is derived from the UniProt Consortium (http://www.uniprot.org/). Distributed under the Creative Commons Attribution-NoDerivs License."^^ . "SEQUENCE 127 AA; 14395 MW; 0DAE0CAAAD5E4E15 CRC64;"^^ . . . . . . "TCP4_HUMAN"^^ . "p14"^^ . "Positive cofactor 4"^^ . "PC4"^^ . "SUB1"^^ . "SUB1 homolog"^^ . . . . . . . . . . . . . . . . . . "MPKSKELVSSSSSGSDSDSEVDKKLKRKKQVAPEKPVKKQKTGETSRALSSSKQSSSSRDDNMFQIGKMRYVSVRDFKGKVLIDIREYWMDPEGEMKPGRKGISLNPEQWSQLKEQISDIDDAVRKL"^^ . "Activated RNA polymerase II transcriptional coactivator p15"^^ .