# Old cogs, new clocks: a conserved protein complex controls developmental and circadian timing

## TL;DR

A new study shows that a protein complex controls both daily rhythms and developmental timing in organisms.

## Contribution

The study identifies a conserved timing module shared between circadian and developmental timing programs.

## Key findings

- LIN-42 forms a functional complex with KIN-20 in C. elegans.
- The LIN-42/KIN-20 complex is a conserved timing module.
- This module is shared between circadian and developmental timing programs.

## Abstract

The circadian clock protein Period and its C. elegans counterpart LIN-42, involved in regulation of daily rhythms and developmental timing, respectively, have long been suspected to function mechanistically in a similar manner. The new study by Spangler et al, (2025) in The EMBO Journal reveals that LIN-42 forms a functional complex with the CkIδ/ε kinase homologue KIN-20, establishing the first conserved timing module shared between circadian and developmental timing programs.

A recent study identifies a conserved timing module composed of LIN-42/PER and KIN-20/CK1that is shared by circadian and developmental timing programs.