Phage small proteins play large roles in phage–bacterial interactions

Phages have wide influence on bacterial physiology, and likewise, bacterial processes impinge on phage biology. Key to these interactions are phage small proteins (<100 aa). Long underappreciated, recent work has revealed millions of phage small proteins, and increasingly, mechanisms by which they function to dictate phage and/or bacterial behavior and evolution. Here, we describe select phage small proteins that mediate phage–bacterial interactions by modulating phage lifestyle decision-making components or by altering host gene expression.