Overview of small proteins encoded by bacterial dual-function small RNAs

Small RNAs (sRNAs) are widely used by bacteria to regulate diverse biological processes. Although they are generally considered "non-coding", some sRNAs (called dual-function sRNAs) have been found to encode small proteins, which are usually less than 50 amino acids in length and have long been overlooked due to significant challenges in their annotation and biochemical detection. However, in the past few decades, an increasing number of small proteins encoded by dual-function sRNAs have been reported. Previous reviews of dual-function sRNAs have mainly focused on their base-pairing nucleic acid functions, with less emphasis on the nature of their translated peptides, resulting in limited understanding of their full functional scope. This article reviews ten small proteins encoded by dual-function sRNAs and introduces their physiological functions, interacting protein partners, and the research methods used, aiming to provide new perspectives and directions for the study of small proteins and enhance understanding of bacterial regulatory mechanisms mediated by dual-function sRNAs.