Heterochronic protein which controls the choice of stage specific cell fates (By similarity). Regulates the timing of the second larval stage events (L2 events) in the hypodermis (By similarity). May negatively regulate the larval to adult transition via the suppression of the microRNA (miRNA) let-7 during L3 (By similarity). Through this regulatory role, controls the timing of the sexual maturation of the nervous system (By similarity). Plays a role in governing the developmental timing of male tail tip morphogenesis (By similarity). Plays a role in the control of seam cell number and vulval development (By similarity). Component of a complex at least containing lep-2, lin-28 and the long non-coding RNA lep-5, which mediates the degradation of lin-28. Belongs to the lin-28 family.