Hsp70 localizes differently from chaperone Hsc70 in mouse mesoangioblasts under physiological growth conditions.
Mouse A6 mesoangioblasts express Hsp70 even in the absence of cellular stress. Its expression and its intracellular localization were investigated under normal growth conditions and under hyperthermic stress. Immunofluorescence assays indicated that without any stress a fraction of Hsp70 co-localized with actin microfilaments, in the cell cortex and in the contractile ring of dividing cells, while the Hsc70 chaperone did not. Hsp70 immunoprecipitation assays confirmed that a portion of Hsp70 binds actin. Immunoblot assays showed that both proteins were present in the nucleus. After heat treatment Hsp70 and actin continued to co-localize in the leading edge of A6 cells but not on microfilaments. Although Hsp70 and Hsc70 are both basally synthesized they showed different cellular distribution, suggesting an Hsp70 different activity respect to the Hsc70 chaperone. Moreover, we found Hsp70 in the culture medium as it has been described in other cell types.
Dipartimento di Biologia Cellulare e dello Sviluppo, Università di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
Giuseppina
G
Turturici
Fabiana
F
Geraci
Maria Elena
ME
Candela
Giovanni
G
Giudice
Fidelina
F
Gonzalez
Gabriella
G
Sconzo
D000199:Actins / Q000378:metabolism; D000818:Animals; D002455:Cell Division / Q000502:physiology; D002460:Cell Line; D005920:Glomerular Mesangium / Q000166:cytology / Q000502:physiology; D050883:HSC70 Heat-Shock Proteins / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D051379:Mice; D018832:Molecular Chaperones / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000502:physiology; D013312:Stress, Physiological
D000199:Actins; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D018832:Molecular Chaperones