4 | Conclusion
As microproteins are increasingly linked with roles in human health and disease, elucidating their numbers and biological roles will be ever more essential. Regarding the complete annotation of microproteins, while there are still inconsistencies in the specific sORF loci identified across ribosome profiling studies, most recent studies detect comparable numbers of translated sORFs in a given organism. This developing consensus suggests that meta-analysis of ribosome profiling data has the potential to resolve complete sORF translatomes in the near future. As this effort advances, large-scale CRISPR screens and other methods can be (re-)employed to identify functional sORFs on scale. However, it is important to note that most sORF functional screens to date have focused on cell proliferation/survival, protein-protein interactions, and/or conservation, thus potentially screening out sORFs with roles beyond these readouts. For example, microproteins with clear involvement in yeast mating and cellular responses to stress have been reported, but can be species-specific, nonessential and may not undergo long-lived interactions with other proteins, and thus would not appear as hits in most functional screens to date. Thus, alternative avenues to identify microproteins with potential functions are needed. Given the exquisite link between protein three-dimensional structure and function, investigation of microprotein structure holds tremendous promise to address this need. The advent of AlphaFold, combined with the rapidly increasing number of solved microprotein structures and experimentally characterized intrinsically disordered microproteins, including those described above, are already contributing to the improved power of structural prediction to generate functional hypotheses about uncharacterized microproteins. Experimental structural investigations are also providing critical mechanistic insights into how microproteins exert their functions, for example in allosteric regulation of target proteins. Combined with insights into disease-associated microprotein mutations and dysregulation, structural and mechanistic information may also pave the way to determining whether microproteins and/or their binding partners are druggable in the future.