STMN2STMN4

STMN2STMN4 is not a standard gene symbol in human genetics; it most commonly refers to the two paralogous genes STMN2 (stathmin-2, also known as SCG10) and STMN4 (stathmin-4). Both belong to the stathmin family of microtubule-regulating proteins and encode small cytosolic phosphoproteins that influence microtubule dynamics by interacting with tubulin dimers and promoting microtubule catastrophe. Their activity is tightly controlled by phosphorylation, which modulates their affinity for tubulin.

STMN2 is highly enriched in neurons, where it participates in axon growth, branching, and growth-cone dynamics during development and regeneration. STMN4 shares functional similarities as a regulator of microtubule stability but has a different expression pattern and regulatory controls that reflect its distinct tissue distribution and developmental roles. Both proteins contribute to neuronal morphology and intracellular transport by shaping the microtubule network.

Phosphorylation of stathmin proteins occurs at multiple serine residues, mediated by kinases such as MAPKs, CaMKII, and PKA. Phosphorylation generally reduces their tubulin-binding activity, allowing microtubule growth to proceed when needed. This regulatory mechanism links extracellular signals to cytoskeletal remodeling, influencing neurite outgrowth and synaptic plasticity.

Clinical relevance is most established for STMN2. Altered STMN2 expression and processing have been observed in neurodegenerative contexts, and truncated STMN2 transcripts have been reported in association with TDP-43 pathology, making STMN2 a potential biomarker of axonal injury in diseases such as ALS and FTD. STMN4’s disease associations are less well characterized but are studied within the broader context of neuronal microtubule regulation.

There is no widely recognized fusion gene or combined entity officially named STMN2STMN4; the term most often denotes the two related genes or comparative study of their functions.