The Department of Biomedicine

BBB seminar: Matti S. Airaksinen

LRRTM family of synaptic cell adhesion proteins

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Matti S. Airaksinen
Department of Anatomy, Institute of Biomedicine, University of Helsinki, Finland

The LRRTM (leucine-rich repeat transmembrane) family comprises four neuron-specific transmembrane proteins (LRRTM1 to LRRTM4) that act as synaptogenic cell adhesion molecules and are thought to organize the molecular composition and thus functional properties of excitatory synapses. The LRRTMs contain extracellular leucine-rich repeats (LRRs) and a short cytoplasmic region that interacts with the postsynaptic organizer protein PSD-95. Recent studies have identified neurexins and glypicans as the presynaptic receptors for LRRTMs. These interactions have been shown to be critical for excitatory synapse maturation and function. Evolutionary analysis indicates that the LRRTM emerged in early vertebrates and presumably bound glypicans before acquiring neurexins as binding partners. LRRTM1 is the first gene associated with human handedness. LRRTMs and their receptors have been implicated in the etiologies of Alzheimer’s disease, autism spectrum disorders (ASD) and schizophrenia. We study LRRTM-deficient mice as possible models of these mental illnesses. Ongoing studies also address the role of alternative isoforms of LRRTMs.

Chairperson: Päivi Kettunen, Department of Biomedicine