Retinal ribbon synapses and the potential functional role of TIAM1: A structural and molecular perspective.

Purpose: Retinal and inner ear ribbon synapses are specialized sensory synapses characterized by synaptic ribbons, electron-dense and protein-rich structures that enable rapid and sustained neurotransmitter release. This review aims to examine the molecular architecture of ribbon synapses with a particular focus on the potential involvement of Tiam1, a guanine nucleotide exchange factor implicated in neuronal development and synaptic plasticity. Methods: A comprehensive review of the available literature was conducted to summarize current knowledge on the structural organization and molecular components of ribbon synapses. Particular attention was given to studies investigating Tiam1 expression, function, and its possible role in cytoskeletal remodeling and synaptic regulation. Results: Evidence supports the central role of RIBEYE as the primary structural component of ribbon synapses; however, the regulatory mechanisms governing ribbon formation and function remain incompletely understood. Recent studies suggest a potential contribution of Tiam1 in modulating synaptic organization and function through Rac1 activation and cytoskeletal regulation, although direct experimental evidence in ribbon synapses is still limited. Conclusions: Ribbon synapses are critical for sustained neurotransmission in sensory systems, yet their molecular regulation remains incompletely defined. Tiam1 emerges as a promising candidate molecule that may influence ribbon synapse function. Future experimental studies are needed to clarify its localization, molecular interactions, and contribution to synaptic organization and plasticity.