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Localization of heat shock protein HSPA 6 ( HSP 70B') to sites of transcription in cultured differentiated human neuronal cells following thermal stress

2014; Wiley; Volume: 131; Issue: 6 Linguagem: Inglês

10.1111/jnc.12970

1471-4159

Sam Khalouei, Ari M. Chow, Ian R. Brown,

Endoplasmic Reticulum Stress and Disease

Abstract Heat shock proteins (Hsps) are a set of highly conserved proteins that are involved in cellular repair and protective mechanisms. In order to identify potential stress‐sensitive sites in differentiated SH ‐ SY 5Y human neuronal cells, localization of two inducible members of the HSPA ( HSP 70) family was investigated, namely HSPA 6 ( HSP 70B') and HSPA 1A ( HSP 70‐1). Following heat shock, yellow fluorescent protein ( YFP )‐tagged HSPA 6 and HSPA 1A proteins localized to nuclear speckles that are enriched in RNA splicing factors (identified by SC 35 and SON marker proteins) and then to the granular component of the nucleolus (identified by nucleophosmin). Subsequently, YFP ‐ HSPA 6 protein, but not YFP ‐ HSPA 1A, localized to the periphery of nuclear speckles that are sites of RNA transcription. The HSPA 6 gene is present in the human genome but not in genomes of rat and mouse. Hence, current animal models of neurodegenerative diseases are lacking a potentially protective member of the HSPA family. image Potential stress‐sensitive sites were identified in differentiated human SH‐SY5Y cells by the localization of HSPA6 (HSP70B') and HSPA1A (HSP70‐1) to nuclear components following heat shock. HSPA6 and HSPA1A rapidly moved to nuclear speckles, enriched in RNA splicing factors, then to the granular layer of the nucleolus. Subsequently, HSPA6 exhibited a novel localization not observed for the more widely studied HSPA1A, namely association with the periphery of nuclear speckles that are sites of transcription. HS = heat shock; HSPA6 = HSP70B' protein; HSPA1A = HSP70‐1 protein.