heterogeneous nuclear ribonucleoproteins C1/C2; hnRNP C1 / hnRNP C2 (HNRNPC, HNRPC)

Function

• binds pre-mRNA & nucleates assembly of 40S hnRNP particles
• single HNRNPC tetramers bind 230-240 nucleotides
• trimers of HNRNPC tetramers bind 700 nucleotides
• may play a role in early steps of spliceosome assembly & pre-mRNA splicing
• interacts with poly-U tracts in the 3'-UTR or 5'-UTR of mRNA & modulates stability & the level of translation of bound mRNA molecules
• phosphorylated on Ser-260 & Ser-299 in resting cells
• phosphorylated on Ser-253 & on 1 Ser in the poly-Ser stretch at position 238 in response to hydrogen peroxide
• sumoylated; sumoylation reduces affinity for mRNA
• tetramer composed of 3 copies of isoform C1 & 1 copy of isoform C2
• assembly of 3 tetramers with bound pre-mRNA gives rise to a 19S complex that interacts with HNRNPA2B1 tetramers
• component of the 40S hnRNP particle
• identified in the spliceosome C complex

Structure

• belongs to the RRM HNRPC family, RALY subfamily
• contains 1 RRM domain (RNA recognition motif)

Compartment

nucleus. Note: Component of ribonucleosomes

Alternative splicing

named isoforms=4; C2, C1

More general terms

• heterogeneous nuclear ribonucleoprotein (hnRNP)
• RNA-binding protein
• phosphoprotein

Component of

• spliceosome C complex

Database

• UniProt: http://www.uniprot.org/uniprot/P07910.html
• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=3183
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:3183
• OMIM: https://mirror.omim.org/entry/164020