Usher protein

E, and K which must be assembled in the correct sequence. A chaperonin PapD is also required as is an "usher protein," PapC,50 and also the disulfide exchange protein DsbA (Chapter 10). DsbA helps PapD to form the correct disulfide bridges as it folds and PapD binds and protects the various pilus subunits as they accumulate in the periplasmic space of the host. The usher protein displaces the chaperonin PapD and "escorts" the subunits into the membrane where the extrusion occurs.50 55... 

Uridylate kinase 655 5 -Uridylic acid. See UMP Urocanase reaction 778 Urocanic acid 755,756s Urokinase 634 Uronic acid 164 Uroporphyrin(s) 843 Uroporphyrin I, 845s Urothione 804s, 891 Urticaria 385 Usher protein 364... 

Reiners, J., Nagel-Wolfrum, K., Jurgens, K., Marker, T. and Wolfmm, U. (2006) Molecular basis of human Usher syndrome deciphering the meshes of the Usher protein network provides insights into the pathomechanisms of the Usher disease. Exp. Eye Res. 83, 97-119. 

Of the seven mapped genes underlying Usher I, five have been identified. These included cadherin-23 and myosin-7a, both described above, harmonin and SANS, both scaffold proteins, and protocadherin-15, another member of the cadherin superfamily. Biochemical evidence and phenotypic similarity suggests that these proteins may assemble into a complex [29], although conclusive evidence for such a complex is lacking. 

Usher II is caused by mutations in at least four genes only one, usherin, has been identified. Usherin is an extracellular matrix protein of unknown function it is found in basement membranes in the eye and ear (and in other tissues as well). Similarly, at least two genes underlie Usher III, but only one (clarin-1) has been cloned. The function of clarin-1 is unknown. 

Thanassi, D. G. (2002). Ushers and secretins channels for the secretion of folded proteins across the bacterial outer membrane, J. Mol. Microbiol. Biotechnol., 4,11-20. 

The array of methods now available to analyze both proteins and nucleic acids is ushering in a new disci-... 

A characteristic is the appearance of "nemaline bodies" or thickened Z-discs containing Z-disc proteins. Some hereditary diseases involve nonmuscle myosins. Among these is Usher syndrome, the commonest cause of deaf-blindness. The disease, which results from a defect in the myosin VIA gene, typically causes impairment of hearing and retinitis pigmentosa (Chapter 23).hh... 

PapD and PapC appear to act as molecular escorts, regulating the interactions of each pilus protein. As a molecular chaperone, PapD prevents nonproductive interactions of the subunits and allows the subunits to fold properly. We propose that PapC is a member of a new class of proteins that we have named molecular ushers. The PapC usher acts as... 

Tinel A, Tschopp J (2004) The PIDDosome, a protein complex implicated in activation of caspase-2 in response to genotoxic stress. Science 304 843-846 Tomkins J, Usher P, Slade JY, Ince PG, Curtis A, Bushby K, Shaw PJ (1998) Novel insertion in the KSP region of the neurofilament heavy gene in amyotrophic lateral sclerosis (ALS). Neuroreport 9 3967-3970... 

Reiners, J., Reidel, B., El-Amraoui, A., Boeda, B., Huber, L, Petit, C. and Wolfmm, U. (2003) Differential distribution of harmonin isoforms and their possible role in Usher-1 protein complexes in mammalian photoreceptor cells. Invest. Ophthalmol. Vis. Sci. 44, 5006-5015. 

Reiners, J., van Wijk, E., Marker, X, Zimmermann, U., Jurgens, K., te, B.H., Overlack, N., Roepman, R., Knipper, M., Kremer, H. and Wolfmm, U. (2005b) Scaffold protein harmonin (USHIC) provides molecular links between Usher syndrome type 1 and type 2. Hum. Mol. Genet. 14, 3933-3943. 

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