Figure 2. Absence of STMN2 protein detection in human ALS MNs parallels decreased abundance of Stathmin-2 (STMN2) RNA and absence of functional TDP-43 interaction partners.

(A) Rank-ordered median protein intensities in single CTL or ALS MNs.

(B) Uniquely identified and overlapping proteins detected in ALS or CTL single MNs.

(C) PPI network of proteins uniquely detected in CTL (left) or ALS (right) single MNs; TDP-43 node added manually. Node border: magenta, BioGRID-reported direct or indirect TDP-43 PPIs; purple, downstream TDP-43 splice target STMN2; edges indicate STRING-annotated physical PPIs.

(D) Prevalence of TDP-43 interactors among proteins uniquely detected in CTL MNs, proteins uniquely detected in ALS MNs, or detected in the background human proteome (two-sided Fisher’s exact test).

(E) Dual expression of STMN2 RNA (red) and TDP-43 protein (teal) in ALS and CTL human spinal MNs.

(F) Quantitation of STMN2 RNA abundance in ALS (n = 5) and CTL (n = 10) donors; violin plots show median (dashed line), interquartile range (IQR; dotted lines), range, and Mann-Whitney U test p values.

(G) Cryptic and canonical STMN2 transcript visualization in adjacent ALS MN cross-sections.