quaking protein (Hqk, QKI, HKQ)

Function

• RNA-binding protein
• plays a central role in myelinization
• binds to the 5'-NACUAAY-N(1,20)-UAAY-3' RNA core sequence
• regulates pre-mRNA splicing, mRNA export, mRNA stability & protein translation
• protects & promotes stability of mRNAs such as MBP & CDKN1B to promote oligodendrocyte differentiation
• mRNA transport
  • regulates nuclear export of MBP mRNA
• regulates mRNA splicing of MAG pre-mRNA
• translational repressor
• methylated by PRMT1
• tyrosine phosphorylated at its C-terminus, probably by FYN
  • phosphorylation leads to decreased mRNA-binding affinity
• contains 1 KH domain

Structure

• homodimer, does not require RNA to homodimerize
• forms heterodimer with BICC1

Compartment

nucleus, cytoplasm

Alternative splicing

named isoforms=8

Expression

expressed in the frontal cortex of brain

Pathology

• plays a role in genetic susceptibility to schizophrenia (putative)
• deletion of the QKI gene may play a role in astrocytomas

More general terms

• RNA-binding protein
• nuclear protein
• phosphoprotein

Database

• UniProt: http://www.uniprot.org/uniprot/Q96PU8.html