SPTBN4

SPTBN4, also known as Spectrin Beta, Non-Erythrocytic 4, is a gene that encodes a member of the spectrin family of cytoskeletal proteins. Spectrins are essential components of the cell membrane skeleton, providing structural support and influencing cell shape, membrane stability, and the organization of membrane proteins.

The SPTBN4 protein is a beta-spectrin isoform, characterized by its association with alpha-spectrins to form heterodimers. These heterodimers then self-associate to create higher-order oligomers, forming a meshwork beneath the plasma membrane. Unlike the erythrocytic spectrins (SPTAs and SPTBs), SPTBN4 is primarily expressed in non-erythroid cells, including neurons, epithelial cells, and fibroblasts.

Functions of SPTBN4 include:

• Cell Shape and Stability: Contributing to the mechanical integrity and overall shape of cells.
• Membrane Protein Localization: Interacting with and anchoring specific membrane proteins to designated locations.
• Cell Signaling: Participating in signal transduction pathways by scaffolding signaling molecules.
• Neuronal Development and Function: In neurons, SPTBN4 is involved in axon guidance, synapse formation, and synaptic plasticity.

Mutations in the SPTBN4 gene have been linked to various neurological disorders, including intellectual disability, epilepsy, and neurodevelopmental delays. The specific phenotypic outcome of these mutations can vary depending on the location and nature of the mutation and its impact on protein function. Research suggests that SPTBN4 dysfunction disrupts neuronal connectivity and synaptic transmission, contributing to these neurological conditions. Studies of SPTBN4 also play a role in understanding broader cytoskeletal protein dynamics and their involvement in human health and disease.