Ring-ATPase

Centronuclear myopathy with type 1 fiber hypotrophy is sometimes regarded as a separate entity because many cases show central nuclei only in the hypotrophic type 1 fibers, while the type 2 fibers are morphologically normal. Affected type 1 fibers are even more myotubelike than in other variants of the disorder, with the exception of the severe X-linked form, due to the persistence of a mitochondria-rich core within a peripheral ring of myofibrils. These features are clearly demonstrable using histochemical methods for the localization of SDH activity and myofibrillar ATPase, respectively. 

RING finger proteins may have other domains associated with signal transduction, such as SH3 and STAT domains and domains that bind and effect hydrolysis of nucleotides in signal transduction or for other purposes. These include ATPases, ATP synthases, serine/threonine kinases, GTP-binding domains, ADP-ribosylation domains and AAA-superfamily ATPases (http //home.cancer.gov/lpds/weissman). 

Navon, a., and Goldberg, A. L. Proteins are unfolded on the surface of the ATPase ring before transport into the proteasome. Mol Cell 2001, 8(6), 1339-1349. 

Yoshida, M., and Moeikawa, K. Hexameric ring structure of the ATPase domain of the membrane-integrated metalloprotease FtsH from Thermus thermophilus HB8. Structure (Camb) 2002, 10, 1415-1423. 

Peters, J.-M., Walsh, M. J., and Franke, W. W. An abundant and ubiquitous homo-oligomeric ring-shaped ATPase particle related to the putative vesicle fusion proteins Sec 18p and NSF. EMBOJ. 1990, 9, 1757-1767. 

A recurring feature of all bacteria possessing genuine 20S proteasomes is the existence of a gene, ARC, encoding a more distant member of the AAA family of ATPases, which is found upstream of the proteasome operons (Nagy et al. 1998 De Mot et al. 1999). The recombinant ARC ATPase from Rhodococcus erythropolis is a complex of two six-membered rings with ATPase activity like other proteasomal ATPases it has an N-terminal coiled-coil domain (Wolf et al. 1998). 

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