Global InformationMicropeptide information
Micropeptides (also referred to as microproteins) are polypeptides with a length of less than 100-150 amino acids that are encoded by short open reading frames (sORFs).[1][2][3] In this respect, they differ from many other active small polypeptides, which are produced through the posttranslational cleavage of larger polypeptides.[1][4] In terms of size, micropeptides are considerably shorter than "canonical" proteins, which have an average length of 330 and 449 amino acids in prokaryotes and eukaryotes, respectively.[5] Micropeptides are sometimes named according to their genomic location. For example, the translated product of an upstream open reading frame (uORF) might be called a uORF-encoded peptide (uPEP).[6] Micropeptides lack an N-terminal signaling sequences, suggesting that they are likely to be localized to the cytoplasm.[1] However, some micropeptides have been found in other cell compartments, as indicated by the existence of transmembrane micropeptides.[7][8] They are found in both prokaryotes and eukaryotes.[1][9][10] The sORFs from which micropeptides are translated can be encoded in 5' UTRs, small genes, or polycistronic mRNAs. Some micropeptide-coding genes were originally mis-annotated as long non-coding RNAs (lncRNAs).[11]
Given their small size, sORFs were originally overlooked. However, hundreds of thousands of putative micropeptides have been identified through various techniques in a multitude of organisms. Only a small fraction of these with coding potential have had their expression and function confirmed. Those that have been functionally characterized, in general, have roles in cell signaling, organogenesis, and cellular physiology. As more micropeptides are discovered so are more of their functions. One regulatory function is that of peptoswitches, which inhibit expression of downstream coding sequences by stalling ribosomes, through their direct or indirect activation by small molecules.[11]
- ^ a b c d Crappé J, Van Criekinge W, Menschaert G (2014). "Little things make big things happen: A summary of micropeptide encoding genes". EuPA Open Proteomics. 3: 128–137. doi:10.1016/j.euprot.2014.02.006.
- ^ Makarewich CA, Olson EN (September 2017). "Mining for Micropeptides". Trends in Cell Biology. 27 (9): 685–696. doi:10.1016/j.tcb.2017.04.006. PMC 5565689. PMID 28528987.
- ^ Guillén G, Díaz-Camino C, Loyola-Torres CA, Aparicio-Fabre R, Hernández-López A, Díaz-Sánchez M, Sanchez F (2013). "Detailed analysis of putative genes encoding small proteins in legume genomes". Frontiers in Plant Science. 4: 208. doi:10.3389/fpls.2013.00208. PMC 3687714. PMID 23802007.
- ^ Hashimoto Y, Kondo T, Kageyama Y (June 2008). "Lilliputians get into the limelight: novel class of small peptide genes in morphogenesis". Development, Growth & Differentiation. 50 (Suppl 1): S269–76. doi:10.1111/j.1440-169x.2008.00994.x. PMID 18459982.
- ^ Zhang J (March 2000). "Protein-length distributions for the three domains of life". Trends in Genetics. 16 (3): 107–9. doi:10.1016/s0168-9525(99)01922-8. PMID 10689349.
- ^ Rothnagel J, Menschaert G (May 2018). "Short Open Reading Frames and Their Encoded Peptides". Proteomics. 18 (10): e1700035. doi:10.1002/pmic.201700035. PMID 29691985.
- ^ Anderson DM, Anderson KM, Chang CL, Makarewich CA, Nelson BR, McAnally JR, Kasaragod P, Shelton JM, Liou J, Bassel-Duby R, Olson EN (February 2015). "A micropeptide encoded by a putative long noncoding RNA regulates muscle performance". Cell. 160 (4): 595–606. doi:10.1016/j.cell.2015.01.009. PMC 4356254. PMID 25640239.
- ^ Bi P, Ramirez-Martinez A, Li H, Cannavino J, McAnally JR, Shelton JM, Sánchez-Ortiz E, Bassel-Duby R, Olson EN (April 2017). "Control of muscle formation by the fusogenic micropeptide myomixer". Science. 356 (6335): 323–327. Bibcode:2017Sci...356..323B. doi:10.1126/science.aam9361. PMC 5502127. PMID 28386024.
- ^ Alix E, Blanc-Potard AB (February 2008). "Peptide-assisted degradation of the Salmonella MgtC virulence factor". The EMBO Journal. 27 (3): 546–57. doi:10.1038/sj.emboj.7601983. PMC 2241655. PMID 18200043.
- ^ Burkholder WF, Kurtser I, Grossman AD (January 2001). "Replication initiation proteins regulate a developmental checkpoint in Bacillus subtilis". Cell. 104 (2): 269–79. doi:10.1016/s0092-8674(01)00211-2. hdl:1721.1/83916. PMID 11207367. S2CID 15048130.
- ^ a b Andrews SJ, Rothnagel JA (March 2014). "Emerging evidence for functional peptides encoded by short open reading frames". Nature Reviews. Genetics. 15 (3): 193–204. doi:10.1038/nrg3520. PMID 24514441. S2CID 22543778.