A Localization Screen Reveals Translation Factories and Widespread Co-Translational Protein Targeting

A conserved choreography of mRNAs at centrosomes reveals a localization mechanism involving active polysome transport

“…The results confirmed that the six candidate mRNAs accumulated at centrosomes during interphase and/or mitosis. These transcripts included PCNT and NUMA1 mRNA that were also recently identified by us and others (Sepulveda et al, 2018;Chouaib et al, 2019), as well as several new ones: NIN, BICD2, CCDC88C and CEP350 ( Figure 1B, Table 1). Taking into account ASPM and HMMR that we also recently identified (Chouaib et al, 2019), a total of 8 mRNAs thus localize at centrosomes in human cells.…”

“…These transcripts included PCNT and NUMA1 mRNA that were also recently identified by us and others (Sepulveda et al, 2018;Chouaib et al, 2019), as well as several new ones: NIN, BICD2, CCDC88C and CEP350 ( Figure 1B, Table 1). Taking into account ASPM and HMMR that we also recently identified (Chouaib et al, 2019), a total of 8 mRNAs thus localize at centrosomes in human cells. These transcripts encode proteins that regulate various aspects of centrosome maturation, spindle positioning, and MT dynamics.…”

“…Here, the signal recognition particle (SRP) binds the nascent signal peptide, inhibits translation elongation, and mediates anchoring of the nascent polysome to the SRP receptor on the endoplasmic reticulum, where translation elongation resumes (Gilmore et al, 1982; Walter and Blobel, 1980, 1982). Recently, a few hints, such as puromycin sensitivity, suggested that translation may play a role in the localization of some other types of mRNAs (Sepulveda et al, 2018; Chouaib et al, 2019). Whether this is indeed the case and the mechanisms involved remain however unknown.…”

“…In a following study, 13 mRNAs were annotated as enriched on Drosophila centrosomes in at least one stage/tissue over the full course of embryogenesis (Wilk et al, 2016). In humans, four mRNAs were recently found to localize at centrosomes (PCNT, ASPM, NUMA1 and HMMR; Sepulveda et al, 2018; Chouaib et al, 2019). All these mRNAs all code for centrosomal proteins, suggesting that they are translated locally.…”

“…This could be an elegant and general mechanism that ensures RNA localization and local translation, as it could work at any place in the cell. This could explain why co-translational mRNA targeting appears to be a widespread mechanism in cell lines (Chouaib et al, 2019).…”