Heterogeneous nuclear ribonucleoproteins (hnRNPs) in cellular processes: Focus on hnRNP E1's multifunctional regulatory roles

Abstract

Heterogeneous nuclear ribonucleoproteins (hnRNPs) comprise a family of RNA-binding proteins. The complexity and diversity associated with the hnRNPs render them multifunctional, involved not only in processing heterogeneous nuclear RNAs (hnRNAs) into mature mRNAs, but also acting as trans-factors in regulating gene expression. Heterogeneous nuclear ribonucleoprotein E1 (hnRNP E1), a subgroup of hnRNPs, is a KH-triple repeat containing RNA-binding protein. It is encoded by an intronless gene arising from hnRNP E2 through a retrotransposition event. hnRNP E1 is ubiquitously expressed and functions in regulating major steps of gene expression, including pre-mRNA processing, mRNA stability, and translation. Given its wide-ranging functions in the nucleus and cytoplasm and interaction with multiple proteins, we propose a posttranscriptional regulon model that explains hnRNP E1's widespread functional diversity.

Poly(C)-binding protein 1 (PCBP1) mediates housekeeping degradation of mitochondrial antiviral signaling (MAVS)

“…Our investigation extends the multiple capacity of PCBP1 [43,44] as an E3 ubiquitin ligase adaptor for housekeeping degradation of MAVS [45,46]. Besides, PCBP1 displays some regulatory effects after viral infection ( Figures 3D and 6).…”

“…The unique property of PCBP1 was observed in knockdown studies that point to a housekeeping role for PCBP1 at the quiescent state ( Figure 6). This specificity may serve as another sound piece of evidence for divergent physiological functions of the two proteins as reported elsewhere [40][41][42][43].…”

Insights into the biomedical effects of carboxylated single-wall carbon nanotubes on telomerase and telomeres

“…We also observed removal of PCBP1 protein from telomere after treatment with SWNTs. However, up to now, the real mechanism for PCBP1 protein on telomere regulation has not been fully illustrated 54 , and substantial works are currently needed. Our confocal microscope, ChIP and reciprocal IP results demonstrate that PCBP1 can localize at telomere and interact with TRF1 and TRF2 proteins (Fig.…”

Regulating the regulators: Serine/arginine‐rich proteins under scrutiny

“…In particular, the mammalian hnRNP family consists of at least 24 structurally diverse polypeptides (6). SR proteins constitute a family of about twelve evolutionarily conserved polypeptides (7) that contain one or two N-terminal RNA-recognition motifs (RRMs) and a region of variable length that is enriched in Arg-Ser dipeptides (RS domain).…”