paraspeckle component 1 (paraspeckle protein 1, PSPC1, PSP1)

Function

• regulates, cooperatively with NONO & SFPQ, androgen receptor-mediated gene transcription activity in Sertoli cell lines (putative)
• binds to poly(A), poly(G) & poly(U) RNA homopolymers (putative)
• forms heterodimers with NONO
• found in a RNP complex with CAT2 transcribed nuclear RNA
• interaction with NONO is required for its targeting to paraspeckles & perinucleolar caps
• interacts with SFPQ (putative)
• phosphorylated upon DNA damage, probably by ATM or ATR

Structure

• belongs to the PSPC family
• contains 2 RRM (RNA recognition motif) domains

Compartment

• nucleus, nucleolus, nucleus matrix
• cytoplasm (putative)
• in punctate subnuclear structures localized adjacent to nuclear splicing speckles, called paraspeckles
• colocalizes with NONO & SFPQ in paraspeckles & perinucleolar caps (RNA-dependen)
• may cycle between paraspeckles & nucleolus
• in telophase, when daughter nuclei form, localizes to perinucleolar caps

Alternative splicing

named isoforms=2

Expression

• expressed in pancreas, kidney, skeletal muscle, liver, lung, placenta, brain & heart

More general terms

• nuclear protein
• RNA-binding protein
• phosphoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/Q8WXF1.html