TY - JOUR
T1 - Physiological role of the association complexes of α-crystallin and its substrates on the chaperone activity
AU - Lee, Jiahn Shing
AU - Samejima, Tatsuya
AU - Liao, Jiahn Haur
AU - Wu, Shih Hsiung
AU - Chiou, Shyh Horng
PY - 1998/3/17
Y1 - 1998/3/17
N2 - Previous reports on the chaperone activity of α-crystallin to prevent protein denaturation and thermal aggregation have suggested that partially denatured proteins can bind α-crystallin in its central region. Likewise, β- and γ-crystallin can also be localized to the central cavity of α-crystallin particle in vivo, which provides indirect evidence that α-crystallin can function as a chaperone in the intact lens. In this study, we have further demonstrated that the binding of the substrate proteins to α-crystallin by short-term preincubation may mimic the in vivo conditions of crystallin association. Preheating of α-crystallin with its substrate proteins at 60°C for 20 min resulted in the formation of stable complexes between α-crystallin and its substrates (8.0% of insulin or 5.3% of γ-crystallin was involved in complex formation). Under such conditions, the chaperone activity of α-crystallin to inhibit dithiothreitol-, ultraviolet-, or oxidation-induced protein aggregation can be greatly enhanced. Since UV-irradiation and oxidative stress are common insults to eye lenses under normal physiological conditions, the presence of α/γ and α/β complex in vivo may play an important role to maintain the lens in a transparent state.
AB - Previous reports on the chaperone activity of α-crystallin to prevent protein denaturation and thermal aggregation have suggested that partially denatured proteins can bind α-crystallin in its central region. Likewise, β- and γ-crystallin can also be localized to the central cavity of α-crystallin particle in vivo, which provides indirect evidence that α-crystallin can function as a chaperone in the intact lens. In this study, we have further demonstrated that the binding of the substrate proteins to α-crystallin by short-term preincubation may mimic the in vivo conditions of crystallin association. Preheating of α-crystallin with its substrate proteins at 60°C for 20 min resulted in the formation of stable complexes between α-crystallin and its substrates (8.0% of insulin or 5.3% of γ-crystallin was involved in complex formation). Under such conditions, the chaperone activity of α-crystallin to inhibit dithiothreitol-, ultraviolet-, or oxidation-induced protein aggregation can be greatly enhanced. Since UV-irradiation and oxidative stress are common insults to eye lenses under normal physiological conditions, the presence of α/γ and α/β complex in vivo may play an important role to maintain the lens in a transparent state.
UR - http://www.scopus.com/inward/record.url?scp=0032539764&partnerID=8YFLogxK
U2 - 10.1006/bbrc.1998.8272
DO - 10.1006/bbrc.1998.8272
M3 - 文章
C2 - 9514930
AN - SCOPUS:0032539764
SN - 0006-291X
VL - 244
SP - 379
EP - 383
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -