Insulin mimetics and non-canonical insulin receptor signaling: mechanisms and disease relevance.

Insulin receptor (IR) signaling has traditionally been viewed as a canonical pathway in which insulin binding uniformly activates downstream metabolic and mitogenic responses. However, growing evidence indicates that IR signaling is not monolithic. Instead, IR signaling is increasingly recognized as a context-dependent process in which receptor conformation, spatial organization, and intracellular trafficking shape signaling outcomes. These non-canonical regulatory mechanisms generate distinct signaling states that can differentially regulate metabolic, mitogenic, immune, and neuronal functions. Recent advances in engineered insulin mimetics, including peptides, antibodies, aptamers, and de novo designed ligands, have provided powerful tools to probe this signaling diversity. By stabilizing specific receptor conformations or engagement geometries, these ligands can selectively bias downstream signaling programs. Here we discuss recent insights into how the qualitative features of IR signaling, rather than signaling amplitude alone, determine disease outcomes across diverse pathological contexts. Understanding this signaling diversity may enable the rational design of next-generation insulin mimetics and more precise therapeutic strategies targeting IR pathways.