1hk6 | pdb_00001hk6
RAL BINDING DOMAIN FROM SEC5
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Overview
The exocyst complex is involved in the final stages of exocytosis, when, vesicles are targeted to the plasma membrane and dock. The regulation of, exocytosis is vital for a number of processes, for example, cell polarity, embryogenesis, and neuronal growth formation. Regulation of the exocyst, complex in mammals was recently shown to be dependent upon binding of the, small G protein, Ral, to Sec5, a central component of the exocyst. This, interaction is thought to be necessary for anchoring the exocyst to, secretory vesicles. We have determined the structure of the Ral-binding, domain of Sec5 and shown that it adopts a fold that has not been observed, in a G protein effector before. This fold belongs to the immunoglobulin, superfamily in a subclass known as IPT domains. We have mapped the Ral, binding site on this domain and found that it overlaps with, protein-protein interaction sites on other IPT domains but that it is, completely different from the G protein-geranyl-geranyl interaction face, of the Ig-like domain of the Rho guanine nucleotide dissociation, inhibitor. This mapping, along with available site-directed mutagenesis, data, allows us to predict how Ral and Sec5 may interact.
About this Structure
1HK6 is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Structure of the GTPase-binding domain of Sec5 and elucidation of its Ral binding site., Mott HR, Nietlispach D, Hopkins LJ, Mirey G, Camonis JH, Owen D, J Biol Chem. 2003 May 9;278(19):17053-9. Epub 2003 Mar 6. PMID:12624092
Page seeded by OCA on Tue Nov 20 16:37:08 2007
