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Synaptopodin, a molecule involved in the formation of the dendritic spine apparatus, is a dual actin/α‐actinin binding protein
Author(s) -
Kremerskothen Joachim,
Plaas Christian,
Kindler Stefan,
Frotscher Michael,
Barnekow Angelika
Publication year - 2005
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2004.02888.x
Subject(s) - dendritic spine , synaptopodin , microbiology and biotechnology , cytoskeleton , actin binding protein , actin remodeling of neurons , actin cytoskeleton , actin , mdia1 , biology , chemistry , postsynaptic potential , biochemistry , cell , neuroscience , receptor , hippocampal formation , podocyte , proteinuria , kidney , endocrinology
Synaptopodin (SYNPO) is a cytoskeletal protein that is preferentially located in mature dendritic spines, where it accumulates in the spine neck and closely associates with the spine apparatus. Formation of the spine apparatus critically depends on SYNPO. To further determine its molecular action, we screened for cellular binding partners. Using the yeast two‐hybrid system and biochemical assays, SYNPO was found to associate with both F‐actin and α‐actinin. Ectopic expression of SYNPO in neuronal and non‐neuronal cells induced actin aggregates, thus confirming a cytoplasmic interaction with the actin cytoskeleton. Whereas F‐actin association is mediated by a central SYNPO motif, binding to α‐actinin requires the C‐terminal domain. Notably, the α‐actinin binding domain is also essential for dendritic targeting and postsynaptic accumulation of SYNPO in primary neurons. Taken together, our data suggest that dendritic spine accumulation of SYNPO critically depends on its interaction with postsynaptic α‐actinin and that SYNPO may regulate spine morphology, motility and function via its distinct modes of association with the actin cytoskeleton.