Cell Damage-induced Conformational Changes of the Pro-Apoptotic Protein Bak In Vivo Precede the Onset of Apoptosis

نویسندگان

  • Gareth J. Griffiths
  • Laurence Dubrez
  • Clive P. Morgan
  • Neil A. Jones
  • Jenna Whitehouse
  • Bernard M. Corfe
  • Caroline Dive
  • John A. Hickman
چکیده

Investigation of events committing cells to death revealed that a concealed NH2-terminal epitope of the pro-apoptotic protein Bak became exposed in vivo before apoptosis. This occurred after treatment of human Jurkat or CEM-C7A T-lymphoma cells with the mechanistically disparate agents staurosporine, etoposide or dexamethasone. The rapid, up to 10-fold increase in Bak-associated immunofluorescence was measured with epitope-specific monoclonal antibodies using flow cytometry and microscopy. In contrast, using a polyclonal antibody to Bak, immunofluorescence was detected both before and after treatment. There were no differences in Bak protein content nor in subcellular location before or after treatment. Immunofluorescence showed Bcl-xL and Bak were largely associated with mitochondria and in untreated cells they coimmunoprecipitated in the presence of nonioinic detergent. This association was significantly decreased after cell perturbation suggesting that Bcl-xL dissociation from Bak occurred on exposure of Bak's NH2 terminus. Multiple forms of Bak protein were observed by two dimensional electrophoresis but these were unchanged by inducers of apoptosis. This indicated that integration of cellular damage signals did not take place directly on the Bak protein. Release of proteins, including Bcl-xL, from Bak is suggested to be an important event in commitment to death.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Morphine-induced apoptosis in PC12 cells: role of Bax and Bcl2

Introduction: It was reported that morphine could induce apoptosis in neurons. However, its specific mechanistic pathways remain elusive. The present study was undertaken to determine whether morphine could induce apoptosis in PC12 cells, a neuronal cell line, and the involvement of Bax and Bcl-2, as upstream factors of mitochondrial pathway. Methods: In an experimental study, the viabili...

متن کامل

Effects of hydrogen peroxide-induced oxidative stress on the pattern of pro-apoptotic and anti-apoptotic genes expression during PC12 cells differentiation

Background and Objective: In neurodegenerative disorders, oxidative stress mediated by reactive oxygen species is strongly associated with increased neuronal damages that lead to apoptosis. Pro-apoptotic and anti-apoptotic gene expressions were changed during cell differentiation that affect cell viability and differentiation. This study was conducted to determine the effects of hydrogen peroxi...

متن کامل

Effects of Usnic Acid on Apoptosis and Expression of Bax and Bcl-2 Proteins in Hippocampal CA1 Neurons Following Cerebral Ischemia-Reperfusion

Introduction: Cerebral ischemia-reperfusion causes complex pathological mechanisms that lead to tissue damage, such as neuronal apoptosis. Usnic acid is a secondary metabolite of lichen and has various biological properties including antioxidant and anti-inflammatory activities. This study aimed to investigate the neuroprotective effects of usnic acid on apoptotic cell death and apoptotic-relat...

متن کامل

Oxidative membrane damage and its involvement in gamma radiation-induced apoptotic cell death.

Background: Recent results have provided increasing evidence to support involvement of membrane damage in the mechanism of ionizing radiation induced killing of mammalian cells. These findings have stimulated renewed interest in evaluating the damage to membrane as a primary initiator in radiation-induced cell killing especially in apoptotic death. The present study was aimed to gain deeper ins...

متن کامل

Temporal Correlation Of Bax Expression And Axotomy-Induced Motoneuronal Apoptosis In Adult Rats: A Morphometric, Ultrastructural And Immunohistochemical Study

  Background and Objective: As apoptotic cell death is extremely involved in physiological development and many pathological situations such as cancer and neurodegenerative diseases, the understanding of its molecular machinery can be useful in designing new therapeutic strategies. The present study investigated the temporal expression of the proapoptotic protein Bax in adult spinal motoneuron...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Journal of Cell Biology

دوره 144  شماره 

صفحات  -

تاریخ انتشار 1999