NSL1

NSL1 is a kinetochore component that supports spindle assembly checkpoint signaling by mediating kinetochore targeting of the checkpoint protein Bub3 (PMID:24626182). In Drosophila epithelial tissues, depletion of Nsl1 causes significant aneuploidy, and when apoptosis is blocked, this chromosomal instability drives tumor-like growth accompanied by JNK-dependent induction of the mitogenic factor Wingless and the matrix-remodeling factor MMP1 (PMID:24626182). Beyond this single-organism characterization, no further mechanistic detail on NSL1 has been established in the available corpus.

1. 2014 Medium

   Establishing how the spindle assembly checkpoint protein Bub3 is recruited to kinetochores, and what the consequences of failure are, this work placed Nsl1 as the factor required for Bub3 kinetochore targeting and linked its loss to aneuploidy-driven tumorigenesis.

   Evidence RNAi depletion in Drosophila epithelial tissues with apoptosis blockade, scoring aneuploidy, tumor-like growth, and JNK target induction (Wingless, MMP1)

   PMID:24626182

   Open questions at the time

   • Direct molecular interaction between Nsl1 and Bub3 not biochemically resolved
   • Mechanism by which aneuploidy activates JNK signaling not established
   • Findings limited to a single lab and Drosophila model; human NSL1 function not directly tested

• Whether NSL1 acts within a defined kinetochore subcomplex, how it physically engages Bub3, and whether its checkpoint role is conserved in mammalian cells remain open.
• No structural or biochemical characterization of NSL1-containing complexes in the corpus
• No mammalian validation of the Bub3-targeting role