Calcium-dependent transcriptional repressor that binds to the DRE element of genes including PDYN and FOS. Affinity for DNA is reduced upon binding to calcium and enhanced by binding to magnesium. Seems to be involved in nociception. Regulatory subunit of Kv4/D (Shal)-type voltage-gated rapidly inactivating A-type potassium channels, such as KCND2/Kv4.2 and KCND3/Kv4.3. Modulates channel expression at the cell membrane, gating characteristics, inactivation kinetics and rate of recovery from inactivation in a calcium-dependent and isoform-specific manner. May play a role in the regulation of PSEN2 proteolytic processing and apoptosis. Together with PSEN2 involved in modulation of amyloid-beta formation (By similarity). Binds to DNA as a homomultimer. Dimerization is induced by binding to calcium (PubMed:18201103). Interacts with the C-terminus of PSEN1 and PSEN2 and with PSEN2 CTF subunit. Associates with KCN1. Component of heteromultimeric potassium channels (PubMed:19713751). Identified in potassium channel complexes containing KCND1, KCND2, KCND3, KCNIP1, KCNIP2, KCNIP3, KCNIP4, DPP6 and DPP10 (PubMed:19713751). Interacts with KCND2 and KCND3 (PubMed:11598014, PubMed:12451113, PubMed:20943905). The sumoylated form is present only in the nucleus. In the presence of PSEN2, associated with the endoplasmic reticulum and Golgi. Highly expressed in brain. Isoform 1 or isoform 4 (T+ forms) are expressed at equal levels with isoform 2 or isoform 3 (T- forms). Primarily detected in the layer V and deep layer VI of the cerebral cortex, the hippocampus, and the entire cerebellum. Expressed at low levels in testis. Also expressed in heart. Palmitoylated. Palmitoylation enhances association with the plasma membrane (By similarity). Proteolytically cleaved by caspase-3. Mice deficient for Csen show a significant decrease of amyloid-beta protein 40 and beta-amyloid protein 42, and display markedly reduced responses in models of acute thermal, mechanical, and visceral pain. Lacks EF-hand domains. Belongs to the recoverin family.