biostudies-literatureKonietzny AGemeinnützige Hertie-StiftungEuropean Research CouncilDeutsche ForschungsgemeinschaftAlexander von Humboldt-Stiftunge106523https://www.ebi.ac.uk/biostudies/studies/S-EPMC8844991biostudies-literatureUnknown41(4)Excitatory synapses of principal hippocampal neurons are frequently located on dendritic spines. The dynamic strengthening or weakening of individual inputs results in structural and molecular diversity of dendritic spines. Active spines with large calcium ion (Ca²⁺ ) transients are frequently invaded by a single protrusion from the endoplasmic reticulum (ER), which is dynamically transported into spines via the actin-based motor myosin V. An increase in synaptic strength correlates with stable anchoring of the ER, followed by the formation of an organelle referred to as the spine apparatus. Here, we show that myosin V binds the Ca²⁺ sensor caldendrin, a brain-specific homolog of the well-known myosin V interactor calmodulin. While calmodulin is an essential activatorThe EMBO journalCaldendrin and myosin V regulate synaptic spine apparatus localization via ER stabilization in dendritic spines.PMC8844991EXC‐2049‐390688087FOR2419 TP2759661StG‐2017 759661MI1923/1‐2SFB877 B12Demmers JAAMikhaylova MUetrecht CKonietzny AHertrich NGrunewald KGrendel JHan YDekkers DHWBucher MKadek AfalseCaldendrin and myosin V regulate synaptic spine apparatus localization via ER stabilization in dendritic spines.Excitatory synapses of principal hippocampal neurons are frequently located on dendritic spines. The dynamic strengthening or weakening of individual inputs results in structural and molecular diversity of dendritic spines. Active spines with large calcium ion (Ca²⁺ ) transients are frequently invaded by a single protrusion from the endoplasmic reticulum (ER), which is dynamically transported into spines via the actin-based motor myosin V. An increase in synaptic strength correlates with stable anchoring of the ER, followed by the formation of an organelle referred to as the spine apparatus. Here, we show that myosin V binds the Ca²⁺ sensor caldendrin, a brain-specific homolog of the well-known myosin V interactor calmodulin. While calmodulin is an essential activator2022-01-01T00:00:00Z2022 Feb2026-03-27T16:43:30.941Z2025-02-19T03:58:51.006ZS-EPMC88449913493515910.15252/embj.2020106523