Positive regulator of amyloid protein aggregation and proteotoxicity (PubMed:20723760, PubMed:22854022, PubMed:31034892). Induces conformational changes in amyloid proteins, such as APP, HTT, and SNCA, driving them into compact formations preceding the formation of aggregates (PubMed:20723760, PubMed:22854022, PubMed:31034892). Interacts with SNCA; this interaction promotes the aggregation of SNCA. Isoform Long is predominantly expressed in heart, brain and skeletal muscle. Isoform Short and Isoform Long are expressed throughout the central nervous system, including spinal cord. Belongs to the SERF family.