| Title | FGF13 is not secreted from mouse neurons. |
| Publication Type | Journal Article |
| Year of Publication | 2026 |
| Authors | Malvezzi M, Zhang H, Towers P, Lyden DC, Marx SO, Pitt GS |
| Journal | JCI Insight |
| Volume | 11 |
| Issue | 1 |
| Date Published | 2026 Jan 09 |
| ISSN | 2379-3708 |
| Keywords | Animals, Cell Membrane, Cells, Cultured, Fibroblast Growth Factors, HEK293 Cells, Humans, Mice, Neurons, Proteomics, Voltage-Gated Sodium Channels |
| Abstract | FGF13, a noncanonical fibroblast growth factor (FGF) and member of the fibroblast growth factor homologous factor (FHF) subset, lacks a signal sequence and was previously reported to remain intracellular, where it regulates voltage-gated sodium channels (VGSCs) at least in part through direct interaction with the cytoplasmic C-terminus of VGSCs. Recent reports suggest FGF13 is secreted and regulates neuronal VGSCs through interactions with extracellular domains of integral plasma membrane proteins, yet supportive data are limited. Using rigorous positive and negative controls, we show that transfected FGF13 is not secreted from cultured cells in a heterologous expression system, nor is endogenous FGF13 secreted from cultured neurons. Furthermore, using multiple unbiased screens including proximity labeling proteomics, our results suggest FGF13 remains within membranes and is unavailable to interact directly with extracellular protein domains. |
| DOI | 10.1172/jci.insight.195998 |
| Custom 1 | |
| Alternate Journal | JCI Insight |
| PubMed ID | 41289026 |
| PubMed Central ID | PMC12890474 |
| Grant List | R01 CA218513 / CA / NCI NIH HHS / United States R01 HL160089 / HL / NHLBI NIH HHS / United States R01 HL177538 / HL / NHLBI NIH HHS / United States |