Janusein and EB Cooperate to Enhance Microtubule Plus-end Catastrophe

Janusein (ZC2HC1A) is a conserved microtubule-associated protein that cooperates with EB proteins to promote microtubule plus-end catastrophe, with fragment-specific effects.

• Why it matters: EB proteins organize microtubule plus ends, but how EB-associated factors modulate the growth-to-catastrophe transition is not fully understood.
• What they did: Using spatially resolved proximity proteomics, the study identified Janusein and tested its behavior at low versus higher expression, plus in vitro assays with EB proteins and fragment-specific activity.
• The result: Janusein loss caused spindle defects in human cells, while its C-terminal fragment supported elongation and its N-terminal fragment promoted catastrophe with EB proteins, consistent with simulations and mutational data.