Integrins 3-propeller domain

The N-terminal region of the integrin o-subunit contains seven repeats of about 60 amino acids, which fold into a seven-bladed /Lpropeller domain (Springer, 1997 Xiong et al, 2001) (Fig. 2A). A /3-propeller domain with the same topology is also found in the trimeric G-protein /3-subunit. The... 

Springer, T. A. (1997). Folding of the N-terminal, ligand-binding region of integrin a-subunits into a /1-propeller domain. Proc. Natl. Acad. Sd. USA 94, 65-72. 

Figure 20 The N-terminal /3-propeller domain of a-chain in integrin a3/3v (1JV2) contains seven repeated blades. Each blade (shown in one color) comprises four aligned /3-strands. Four calciiun ions boimd in this domain are located at blades 4-7...

The Sema domain consisting of about 500 amino acids is characterized by highly conserved cysteine residues that form intramolecular disulfide bonds. Crystal structures have revealed that the Sema domain folds in the manner of the (3 propeller topology which is also found in integrins or the low-density lipoprotein (LDL) receptors. Sema domains are found in semaphorins, plexins and in the receptor tyrosine kinases Met and Ron. 

In integrins that contain I domains, the I domain binds ligand, whereas the /3-propeller and I-like domains have a regulatory role (Fig. 3D—H and Fig. 6B) (Lu et al, 2001b,c). The bottom of the I domain is connected at its N- and G-termini to blades 2 and 3 of the /3-propeller, respectively (Figs. 2A, 4A). A linker of 15 residues G-terminal to the I domain must therefore... 

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