| Type: | Conserved_site | Name: | Dynamin, GTPase region, conserved site |
| Description: | The P-loop guanosine triphosphatases (GTPases) control a multitude of biological processes, ranging from cell division, cell cycling,and signal transduction, to ribosome assembly and protein synthesis. GTPases exert their control by interchanging between an inactive GDP-bound state andan active GTP-bound state, thereby acting as molecular switches. The common denominator of GTPases is the highly conserved guanine nucleotide-binding (G)domain that is responsible for binding and hydrolysis of guanine nucleotides.Members of the dynamin GTPase family appear to be ubiquitous. They catalysediverse membrane remodelling events in endocytosis, cell division, and plastid maintenance. Their functional versatility also extends to other core cellularprocesses, such as maintenance of cell shape or centrosome cohesion. Members of the dynamin family are characterised by their common structure and byconserved sequences in the GTP-binding domain. The minimal distinguishing architectural features that are common to all dynamins and are distinct fromother GTPases are the structure of the large GTPase domain (~280 amino acids) and the presence of two additional domains: the middle domain and the GTPaseeffector domain (GED), which are involved in oligomerisation and regulation of the GTPase activity. In many dynamin family members, thebasic set of domains is supplemented by targeting domains, such as: pleckstrin-homology (PH) domain, proline-rich domains(PRDs), or by sequences that target dynamins to specific organelles, such as mitochondria and chloroplasts [, , ].The dynamin-type G domain consists of a central eight-stranded beta-sheet surrounded by seven alpha helices and two one-turn helices.It contains the five canonical guanine nucleotide binding motifs (G1-5). The P-loop (G1) motif (GxxxxGKS/T) is also present in ATPases (Walker A motif) andfunctions as a coordinator of the phosphate groups of the bound nucleotide. A conserved threonine in switch-I (G2) and the conserved residues DxxG ofswitch-II (G3) are involved in Mg(2+) binding and GTP hydrolysis. The nucleotide binding affinity of dynamins is typically low, with specificity forGTP provided by the mostly conserved N/TKxD motif (G4). The G5 or G-cap motif is involved in binding the ribose moiety [, , ].This entry represents a conserved site in the dynamin-type G domain and is based on a highly conserved region downstream of the ATP/GTP-binding motif 'A' (P-loop). | Short Name: | Dynamin_GTPase_CS |
