MRPL33 gene encodes a large mitoribosomal subunit protein, which may be involved in mitochondrial translation. Although two splice variants of MRPL33 have been described, its splicing regulation remains elusive. Here we observed that inclusion of alternative exon 3 was greatly promoted in a panel of human cancer cells. Depletion of the exon 3-containing long isoform of MRPL33 (MRPL33-L) led to impaired proliferation and increased apoptosis in cancer cell lines and in a xenograft model. MRPL33-L knockdown could also induce mitochondrial dysfunction including increased accumulation of reactive oxygen species, decreased ATP production and 16 S rRNA levels. We further showed that alternative splicing of MRPL33-L pre-mRNA is regulated by hnRNPK and that knocking down hnRNPK could phenocopy MRPL33-L depletion. More importantly, overexpression of MRPL33-L could increase tumorigenic potential of hnRNPK-depleted cancer cells, likely indicating that hnRNPK mediates tumorigenesis through splicing regulation of MRPL33 pre-mRNA. Finally, we found that inclusion of MRPL33 exon 3 was promoted in human colorectal cancer tissues and this was correlated with hnRNPK levels. In summary, our findings underscore the biological significance of MRPL33-L and hnRNPK in the tumor formation and identifies hnRNPK as a critical splicing regulator of MRPL33 pre-mRNA in cancer cells.

Taken together, hCLP46 enhanced Notch activation and inhibited 293TRex cell proliferation through CDKI signalling.

The two-centre atomic orbital close-coupling method is employed to study the electron capture reactions in collisions of N 5+ and O 6+ ions with ground state atomic hydrogen in the energy range from 0.5 to 200 keV u −1 . The interaction of an active electron with the projectile ion is represented by a model potential. Total and state-selective electron capture cross sections for the dominant and subdominant reaction channels are calculated and compared with the available experimental and theoretical data.