Yeung, T. et al. Receptor activation alters inner surface potential during phagocytosis. Science 313, 347-351

University of Toronto, Toronto, Ontario, Canada
Science (Impact Factor: 33.61). 08/2006; 313(5785):347-51. DOI: 10.1126/science.1129551
Source: PubMed


The surface potential of biological membranes varies according to their lipid composition. We devised genetically encoded
probes to assess surface potential in intact cells. These probes revealed marked, localized alterations in the charge of the
inner surface of the plasma membrane of macrophages during the course of phagocytosis. Hydrolysis of phosphoinositides and
displacement of phosphatidylserine accounted for the change in surface potential at the phagosomal cup. Signaling molecules
such as K-Ras, Rac1, and c-Src that are targeted to the membrane by electrostatic interactions were rapidly released from
membrane subdomains where the surface charge was altered by lipid remodeling during phagocytosis.

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    • "This larger size allows the protrusion of the head group in the aqueous phase, making this lipid functional for biological processes (McLaughlin et al., 2002). In addition, the phosphate groups confer a negative charge to the lipid headgroup, promoting the engagement in electrostatic interactions with protein containing polybasic domains (Yeung et al., 2006; Magalhaes and Glogauer, 2010). "
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    • "Transient transfection of HUVECs was performed using Amaxa (Gaithersburg, MD) nucleofection or the NEON transfection system (Life Technologies, Burlington, Canada) as per the manufacturer's instructions. The expression plasmids used in this study include CX 3 CL1-mCherry, CX 3 CL1-360, CX 3 CL1-Y362A-Y392A, CX 3 CL1- LifeAct-GFP and RFP, GPI-GFP, GT-46 YFP, and the tail of K-Ras-GFP (Kenworthy et al., 2004; Yeung et al., 2006; Durkan et al., 2007; Riedl et al., 2008; Huang et al., 2009; Tole et al., 2010). For gene silencing, HUVECs were electroporated with siRNA directed against human ADAM10 or nontargeting, scrambled siRNA (Santa Cruz Biotechnology , Santa Cruz, CA) on days 0 and 2. Knockdown was confirmed by immunoblotting. "
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    • "We next determined whether ectopic expression of CLIC5A alters the negative surface potential of the plasma membrane inner leaflet in COS-7 cells by co-transfecting them with the surface potential reporter GFP–Kras (Yeung et al., 2006) and CLIC5A or empty vector. Live-cell imaging revealed that the surface potential biosensor GFP–Kras was evenly distributed along the plasma membrane in the absence of CLIC5A. "
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