RhoBTB

RhoBTB

RhoBTB proteins are a subfamily of Rho GTPases, a group of enzymes known for their role as molecular switches in diverse cellular processes. Unlike classical Rho GTPases, which cycle between active GTP-bound and inactive GDP-bound states, RhoBTB proteins are characterized by several distinctive structural features, most notably the presence of a BTB (also known as POZ) domain and a BACK domain, in addition to the Rho GTPase domain.

The BTB domain is a protein-protein interaction module commonly found in transcription factors and cytoskeletal proteins. In RhoBTB proteins, it facilitates self-association (oligomerization) and interaction with other proteins, potentially acting as a platform for assembling multi-protein complexes. The BACK domain is a region of variable length found between the Rho GTPase and BTB domains. Its exact function is not completely understood but is thought to contribute to the stability and regulation of the protein.

The Rho GTPase domain within RhoBTB proteins retains the capacity for GTP binding and hydrolysis, although the regulation of this activity and its functional consequences differ from that of classical Rho GTPases. Some RhoBTB proteins display altered nucleotide binding properties and reduced GTPase activity.

Functionally, RhoBTB proteins have been implicated in a variety of cellular processes, including cytoskeletal organization, cell growth and differentiation, transcriptional regulation, and autophagy. Their roles often appear to be context-dependent and involve interactions with specific binding partners mediated by the BTB domain. Deregulation of RhoBTB proteins has been linked to various human diseases, including cancer and neurological disorders, making them potential therapeutic targets. The precise mechanisms by which RhoBTB proteins exert their diverse effects are still under investigation, and further research is needed to fully elucidate their cellular roles and regulatory mechanisms.