Structural Insights of tBid, the Caspase-8-activated Bid, and Its BH3 Domain

Abstract

Background:The membrane-associated tBid promotes Bax membrane insertion and activation. Results: tBid adopts an extended structure in 1-palmitoyl-2-hydroxy-sn-glycero-3-[phospho-RAC-(1-glycerol)] (LPPG) micelles with its six helices including the BH 3 domain interacting with the micelles. Conclusion: An "on the membrane" binding mode was suggested for tBid interaction with Bax. Significance: Revealing tBid structure on the membrane is key to the understanding of tBid-mediated Bax activation.

Minimalist Model Systems Reveal Similarities and Differences between Membrane Interaction Modes of MCL1 and BAK

“…On the one hand, our SFCCS and FRET results indicate that, relative to the situation found in solution, the likelihood of MCL1⅐cBID heterodimerization increases severely in the presence of mitochondrial CS-like GUV/LUV and less prominently in the presence of mitochondrial CS-like SUV. Based on previous observations, it is likely that liposomes with a mitochondrial CS-like membrane composition generally stimulate MCL1⅐cBID complex formation by triggering exposure of the cBID BH3 motif (42,43). However, why is the level of MCL1⅐cBID heterodimerization higher in mitochondrial CS-like GUV/LUV than in mitochondrial CSlike SUV?…”

“…Alternatively, or in addition, high membrane geometrical curvature and/or CL content may cause membrane insertion and hindering of the cBID r BH3 motif. In fact, it has been reported that cBID inserts the hydrophobic face of its BH3 motif into the hydrophobic interior of highly curved anionic micelles (43).…”

Dynamic Protein Interaction Networks and New Structural Paradigms in Signaling

“…The exception is BID, which adopts a globular, α-helical structure and is cleaved by caspase-8 to a truncated form (tBID), which has a molten globule-like structure with a considerable amount of α-helical structure but lacking a well-defined tertiary fold 269 , that associates with and activates BAX at the outer mitochondrial membrane (OMM). It has been proposed that tBID changes structure upon interacting with the OMM, with its “molten” α-helices disassociating into a “C-shaped”, extended structure 270 . Some members of the BCL-2 protein family are constitutively localized to the OMM (e.g., BAK), while others shuttle between the cytosol and OMM (e.g., BAX, BCL-xL).…”

Solid-state NMR of the Yersinia pestis outer membrane protein Ail in lipid bilayer nanodiscs sedimented by ultracentrifugation

“…Solid-state NMR methods can be used for proteins in a variety of lipid sample environments including: liposomes, supported planar lipid bilayers, macrodiscs, lipid-detergent bicelles, precipitated lipids or nanodisc preparations (Drechsler and Separovic 2003; McDermott 2009; Sharma et al 2010; Maltsev and Lorigan 2011; Park et al 2011; Durr et al 2012; Franks et al 2012; Hong et al 2012; Orwick-Rydmark et al 2012; Park et al 2012; Ding et al 2013; Gopinath et al 2013; Loquet et al 2013; Mors et al 2013; Murray et al 2013; Ni et al 2013; Tang et al 2013; Ullrich and Glaubitz 2013; Wang et al 2013; Weingarth and Baldus 2013; Sackett et al 2014). Solution NMR studies can be performed on membrane proteins in detergent micelles (Arora and Tamm 2001; Fernandez and Wuthrich 2003; Sanders and Sonnichsen 2006; Chill et al 2007; Poget and Girvin 2007; Prosser et al 2007; Teriete et al 2007; Hiller and Wagner 2009; Kim et al 2009; Zhou et al 2008; Berardi et al 2011; Wang and Tjandra 2013; Fox et al 2014) and, more recently, lipid bilayer nanodiscs are being used effectively for solution NMR studies of membrane proteins (Gluck et al 2009; Raschle et al 2009; Shenkarev et al 2009; Shenkarev et al 2010; Etzkorn et al 2013; Hagn et al 2013; Shenkarev et al 2013; Tzitzilonis et al 2013; Bibow et al 2014; Susac et al 2014). …”