Evolutionarily diverged on-switch for actin assembly in fungal endocytosis.

Ldb17 in budding yeast (Saccharomyces cerevisiae) functions as an on-switch for clathrin-mediated endocytic actin assembly, with regulation more complex than constitutively active Dip1.

• Why it matters: Endocytic actin assembly initiation is conserved but incompletely understood, and the budding-yeast mechanism has remained a mystery.
• What they did: The study identifies Ldb17 as the Dip1 homolog and shows it is controlled by coat protein Sla1 through separate recruitment and activation steps.
• The result: The Sla1-dependent regulation was likely lost in the Schizosaccharomyces pombe lineage, revealing evolutionary tinkering of the actin on-switch in endocytosis.