- Al-Azzam, Norah;
- To, Jenny H;
- Gautam, Vaishali;
- Street, Lena A;
- Nguyen, Chloe B;
- Naritomi, Jack T;
- Lam, Dylan C;
- Madrigal, Assael A;
- Lee, Benjamin;
- Jin, Wenhao;
- Avina, Anthony;
- Mizrahi, Orel;
- Mueller, Jasmine R;
- Ford, Willard;
- Schiavon, Cara R;
- Rebollo, Elena;
- Vu, Anthony Q;
- Blue, Steven M;
- Madakamutil, Yashwin L;
- Manor, Uri;
- Rothstein, Jeffrey D;
- Coyne, Alyssa N;
- Jovanovic, Marko;
- Yeo, Gene W
Amyotrophic lateral sclerosis (ALS) is linked to the reduction of certain nucleoporins in neurons. Increased nuclear localization of charged multivesicular body protein 7 (CHMP7), a protein involved in nuclear pore surveillance, has been identified as a key factor damaging nuclear pores and disrupting transport. Using CRISPR-based microRaft, followed by gRNA identification (CRaft-ID), we discovered 55 RNA-binding proteins (RBPs) that influence CHMP7 localization, including SmD1, a survival of motor neuron (SMN) complex component. Immunoprecipitation-mass spectrometry (IP-MS) and enhanced crosslinking and immunoprecipitation (CLIP) analyses revealed CHMP7's interactions with SmD1, small nuclear RNAs, and splicing factor mRNAs in motor neurons (MNs). ALS induced pluripotent stem cell (iPSC)-MNs show reduced SmD1 expression, and inhibiting SmD1/SMN complex increased CHMP7 nuclear localization. Crucially, overexpressing SmD1 in ALS iPSC-MNs restored CHMP7's cytoplasmic localization and corrected STMN2 splicing. Our findings suggest that early ALS pathogenesis is driven by SMN complex dysregulation.