Membrin

Membrin is a member of the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) protein family that plays a key role in membrane fusion during the early secretory pathway. It participates in the fusion of endoplasmic reticulum (ER)-derived transport vesicles with the cis-Golgi network, enabling proper trafficking and processing of secretory cargo.

In humans, membrin is encoded by the GOSR1 gene and is commonly referred to by the protein name membrin. It forms a SNARE complex with syntaxin 5, Bet1-like protein (Bet1L), and Sec22b to drive ER-to-Golgi transport. This complex is essential for efficient secretion and for maintaining the organization of Golgi processing pathways.

Membrin is broadly expressed, with prominent expression in neural tissue, reflecting a critical role in neuronal secretory pathways. Its function is essential for proper development and cellular homeostasis; disruption of membrin can impair ER-Golgi trafficking and affect neuronal function in model systems.

Genetic variants in GOSR1 have been associated with rare human neurological disorders in some families, highlighting the importance of membrin in the nervous system. However, the full spectrum of clinical implications remains under investigation, and such associations are not yet fully clarified.

Structurally, membrin is a membrane-anchored SNARE with a cytosolic SNARE motif that participates in complex formation and a C-terminal transmembrane helix that anchors it to membranes. The protein is evolutionarily conserved from yeast to humans, reflecting its fundamental role in vesicular trafficking and membrane fusion.