Rabbit Anti-Human PCBP1 (a.a. 201-300) Polyclonal antibody

Transforming growth factor beta (TGF-beta) induces epithelial-mesenchymal transition (EMT) accompanied by cellular differentiation and migration. Despite extensive transcriptomic profiling, identification of TGF-beta-inducible, EMT-specific genes during metastatic progression of lung cancer remains elusive. Here, we functionally validate a previously described post-transcriptional pathway by which TGF-beta modulates expression of interleukin-like EMT inducer (ILEI), and EMT itself. We show that poly r(C)-binding protein 1 (PCBP1) binds ILEI transcript and repress its translation. TGF-beta activation leads to phosphorylation at serine-43 of PCBP1 by protein kinase B beta/Akt2, inducing its release from the ILEI transcript and translational activation. Modulation of hnRNP E1 expression modification altered TGF-beta-mediated reversal of translational silencing of ILEI transcripts and EMT. Furthermore, ILEI could induce, as well as maintain, CD24(low)CD44(high) subpopulation in A549 cells treated with TGF-beta, which might explain its capability to induce metastatic progression. These results thus validate the existence of an evolutionary conserved TGF-beta-inducible post-transcriptional regulon that controls EMT and subsequent metastatic progression of lung cancer.

The small heat shock protein HSPB1 (Hsp27) is an ubiquitously expressed molecular chaperone able to regulate various cellular functions like actin dynamics, oxidative stress regulation and anti-apoptosis. So far disease causing mutations in HSPB1 have been associated with neurodegenerative diseases such as distal hereditary motor neuropathy, Charcot-Marie-Tooth disease and amyotrophic lateral sclerosis. Most mutations in HSPB1 target its highly conserved a-crystallin domain, while other mutations affect the C-or N-terminal regions or its promotor. Mutations inside the a-crystallin domain have been shown to enhance the chaperone activity of HSPB1 and increase the binding to client proteins. However, the HSPB1-P182L mutation, located outside and downstream of the a-crystallin domain, behaves differently. This specific HSPB1 mutation results in a severe neuropathy phenotype affecting exclusively the motor neurons of the peripheral nervous system. We identified that the HSPB1-P182L mutant protein has a specifically increased interaction with the RNA binding protein poly(C) binding protein 1 (PCBP1) and results in a reduction of its translational repressive activity. RNA immunoprecipitation followed by RNA sequencing on mouse brain lead to the identification of PCBP1 mRNA targets. These targets contain larger 3'-and 5'-UTRs than average and are enriched in an RNA motif consisting of the CTCCTCCTCCTCC consensus sequence. Interestingly, next to the clear presence of neuronal transcripts among the identified PCBP1 targets we identified known genes associated with hereditary peripheral neuropathies and hereditary spastic paraplegias. We therefore conclude that HSPB1 can mediate translational repression through interaction with an RNA binding protein further supporting its role in neurodegenerative disease.