Chemokine transmembrane helix

Blanpain C, Doranz BJ, Bondue A, et al. The core domain of chemokines binds CCR5 extracellular domains while their amino terminus interacts with the transmembrane helix bundle. J Biol Chem 2003 278(7) 5179-5187. 

Govaerts C, Blanpain C, Deupi X, et al. The TXP motif in the second transmembrane helix of CCR5. A structural determinant of chemokine-induced activation. J Biol Chem 2001 276(16) 13217-13225. 

Blanpain, C., Doranz, B. J., Bondue, A., Govaerts, C., De Leener, A., Vassart, G., Dorns, R. W., Proudfoot, A., and Parmentier, M. (2003). The core domain of chemokines binds CCR5 extracellular domains while their amino terminus interacts with the transmembrane helix bundle. / Biol. Chem. 278, 5179-5187. 

It is unknown whether or not TMVI movements play a role in the CCR5 receptor activation mechanism. Overall, a molecular understanding of activation mechanism for CCR5 and other chemokine receptors requires further biophysical studies of transmembrane helix positions and displacements. 

Govaerts, C., Blanpain, C., Deupi, X., Ballet, S., Ballesteros,J. A., Wodak, S.J., Vassart, G., Pardo, L., and Parmentier, M. (2001). The TXP motif in the second transmembrane helix of CCR5. A structural determinant of chemokine-induced activation. J. Biol. Chem. 276,13217-13225. 

FIGURE 1 This cartoon illustrates the secondary structure typical of a CC chemokine receptor. The seven-transmembrane (TM) helices in the bundle are depicted as cylinders and are held together by disulphide bonding of conserved cysteine residues (yellow). The N-terminus is negatively charged and binds the predominantly basic chemokine, while the intracellular C-terminus is rich in serine and threonine residues, some of which undergo phosphorylation following receptor activation. The DRY motif of TM helix 3 is also illustrated. 

---