TMA16

TMA16 is a factor associated with the human pre-60S ribosomal particle, positioned between the 5S RNA and the P0 stalk during the late nuclear maturation steps of large ribosomal subunit assembly (PMID:32669547). Cryo-EM analysis of pre-60S particles isolated through the nuclear export factor NMD3 places TMA16 at this site in assembly intermediates captured immediately before and after nuclear export, linking it to the stages of 60S maturation that bridge the nucleus and cytoplasm (PMID:32669547). Beyond this structural localization (PMID:32669547), no further mechanistic detail, biochemical activity, or interaction network for TMA16 has been characterized in the available corpus.

1. 2020 High

   Whether TMA16 participates in human ribosome biogenesis and where it acts on the maturing subunit was unknown; visualizing it within export-stage pre-60S particles established it as a late large-subunit assembly factor positioned at the 5S RNA/P0 stalk interface.

   Evidence Cryo-EM structural analysis of human pre-60S ribosomal particles isolated via the nuclear export factor NMD3

   PMID:32669547

   Open questions at the time

   • No biochemical activity or function assigned to TMA16 within the particle
   • Mechanism of recruitment and release relative to nuclear export is not defined
   • Effect of TMA16 depletion on 60S maturation or cell growth not tested

• It remains unknown what molecular activity TMA16 contributes to pre-60S maturation and how its association is coordinated with the 5S RNP and stalk assembly.
• No functional or loss-of-function characterization in the available corpus
• No defined binding partners beyond structural proximity to 5S RNA and P0 stalk