Membrane Targeting: Methods

Abstract

The responsiveness of cells to external signals, or cell signalling, involves highly regulated sequences of biochemical reactions at the plasma membrane. When receptor proteins in the outer surface of the plasma membrane are activated by environmental signals, they undergo shape change or chemical modification to assemble internal proteins into an organised complex on the inner surface. Specific protein domains and lipids (fats) that are physically attached to proteins tether key components of this complex to the lipid bilayer of the membrane. Scientists have developed cell‐based and chemical techniques that allow them to introduce specific membrane‐targeting motifs into proteins to produce and study how this may alter cell behaviour. As a result, a great deal has been learned about the molecular basis of membrane targeting by lipid‐modified proteins. This knowledge holds a promise for the rational design of new compounds to prevent defective membrane targeting that could lead to abnormal signalling and the development of diseases.

Key Concepts:

  • Lipid bilayers provide the fundamental architecture of biological membranes.

  • The two‐dimensional surface of membranes provides a structural framework to organise multiple signalling proteins.

  • Proteins target membranes using globular domains and lipids that are covalently attached to them.

  • The most common lipid‐based membrane‐targeting motifs in the interior of the cell include modification of cysteine and glycine amino acids by acyl and prenyl groups.

  • G‐proteins are the quintessential examples of membrane targeting by lipidation.

  • Modern cell biology and chemical biology techniques can be used to artificially attach lipids to proteins.

  • Prevention of defective membrane targeting is being pursued as a new therapeutic strategy.

Keywords: fatty acid modification; lipid bilayer; membrane proteins; protein design; chimaeric protein; chemical biology; computational biology

Figure 1.

A schematic example for the assembly of multiple signalling proteins on the plasma membrane. Activation of the lipid‐modified membrane‐associated Ras proteins (RAS*) triggers the formation of a cluster of multiple proteins of the MAPK module (Raf, MEK and ERK) and scaffold proteins (Galectin and KSR1).

close

References

Abankwa D, Gorfe AA and Hancock JF (2007) Ras nanoclusters: molecular structure and assembly. Seminars in Cell and Developmental Biology 18(5): 599–607.

Abankwa D, Gorfe AA and Hancock JF (2008a) Mechanisms of Ras membrane organization and signalling: Ras on a rocker. Cell Cycle 7(17): 2667–2673.

Abankwa D, Hanzal‐Bayer M, Ariotti N et al. (2008b) A novel switch region regulates H‐ras membrane orientation and signal output. Embo Journal 27(5): 727–735.

Barbacid M (1987) Ras genes. Annual Review of Biochemistry 56: 779–827.

Baumforth KR, Nelson PN, Digby JE, O'Neil JD and Murray PG (1999) Demystified … the polymerase chain reaction. Molecular Pathology 52(1): 1–10.

Bhardwaj N, Stahelin RV, Langlois RE, Cho W and Lu H (2006) Structural bioinformatics prediction of membrane‐binding proteins. Journal of Molecular Biology 359(2): 486–495.

Bhardwaj N , Stahelin RV, Zhao G, Cho W and Lui H (2007) MeTaDoR: a comprehensive resource for membrane targeting domains and their host proteins. Bioinformatics 23(22): 3110–3112.

Brunsveld L, Waldmann H and Huster D (2009) Membrane binding of lipidated Ras peptides and proteins – the structural point of view. Biochimica Biophysica Acta 1788(1): 273–288.

Gorfe AA (2010) Mechanisms of allostery and membrane attachment in Ras GTPases: implications for anti‐cancer drug discovery. Current Medicinal Chemistry 17(1): 1–9.

Gorfe AA, Baron R and McCammon JA (2008) Water‐membrane partition thermodynamics of an amphiphilic lipopeptide: an enthalpy‐driven hydrophobic effect. Biophysical Journal 95(7): 3269–3277.

Hancock JF (2006) Lipid rafts: contentious only from simplistic standpoints. Nature Reviews Molecular Cell Biology 7(6): 456–462.

Hancock JF, Magee AI, Childs JE and Marshall CJ (1989) All ras proteins are polyisoprenylated but only some are palmitoylated. Cell 57(7): 1167–1177.

Harding AS and Hancock JF (2008) Using plasma membrane nanoclusters to build better signaling circuits. Trends in Cell Biology 18(8): 364–371.

Janosi L and Gorfe AA (2010) Segregation of negatively charged phospholipids by the polycationic and farnesylated membrane anchor of Kras. Biophysical Journal 99(11): 3666–3674.

Karnoub AE and Weinberg RA (2008) Ras oncogenes: split personalities. Nature Reviews Molecular Cell Biology 9(7): 517–531.

Nicolini C, Baranski J, Schlummer S et al. (2006) Visualizing association of N‐ras in lipid microdomains: influence of domain structure and interfacial adsorption. Journal of American Chemical Society 128(1): 192–201.

Vetter IR and Wittinghofer A (2001) The guanine nucleotide‐binding switch in three dimensions. Science 294(5545): 1299–1304.

Waldmann V and Rabes HM (1996) What's new in ras genes? Physiological role of ras genes in signal transduction and significance of ras gene activation in tumorigenesis. Pathology – Research and Practice 192(9): 883–891.

Wedegaertner PB, Wilson PT and Bourne HR (1995) Lipid modifications of trimeric G proteins. Journal of Biological Chemistry 270(2): 503–506.

Wright LP and Philips MR (2006) Thematic review series: lipid posttranslational modifications. CAAX modification and membrane targeting of Ras. Journal of Lipid Research 47(5): 883–891.

Further Reading

Casey PJ (1995) Protein lipidation in cell signaling. Science 268: 221–225.

Cereijido M, Contreras RJ, Shoshani L and Garcıa‐Villegas MR (2003) Membrane targeting. Progress in Biophysics & Molecular Biology 81: 81–115.

Stickney JT, Bocoden MA and Buss JE (2001) Targeting proteins to membranes, using signal sequences for lipid modifications. Methods in Enzymology 332: 64–77.

Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Gorfe, Alemayehu A, and Hocker, Harrison J(Jan 2012) Membrane Targeting: Methods. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0002615.pub2]