Escape of ACBD3 (green) from fragmented Golgi (red) allows it to bind Numb during mitosis.

ZHONG/ELSEVIER

The Golgi hides the partner of a stem-cell fate protein, according to results from Yan Zhou, Weimin Zhong (Yale University, New Haven, CT), and colleagues. Only when its partner is briefly freed during Golgi disassembly can Numb defend the undifferentiated state.

Numb has a paradoxical role in cell fate: when a neuronal progenitor divides, Numb keeps one daughter in the progenitor state by inhibiting Notch. Yet Numb is also needed for neuronal differentiation. To solve this mystery, Zhong's group fished for Numb's binding partners. They found a Golgi protein called ACBD3 whose brief cytosolic appearances during mitosis turned Numb into a supporter of the progenitor fate.

During progenitor division, Numb is sent to one daughter, where it carries on the progenitor fate. The authors found that Numb's binding to...

The Rockefeller University Press
2007
The Rockefeller University Press
2007
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