RESUMO
RhoA, RhoB and RhoC GTPases are over 85% identical at the amino acid level, with RhoA and RhoC differing at only one residue (43) across the initial two-thirds of their sequences. A putative regulatory distinction between the molecules is their capacity to be uniquely activated by guanine nucleotide exchange factors (GEFs). We hypothesize that variation of amino acid residue 43 between RhoA/B (valine) and RhoC (isoleucine) impacts GEF activity. Direct participation of residue 43 in GEF-catalyzed exchange was confirmed by the observation that mutation of this position to a threonine reduced GEF-catalyzed nucleotide exchange activity in vitro (Vav2, XPLN, GEFT, Dbl and Dbs) and greatly depressed RhoA and RhoC GTP-loading profiles in cell lysates. Using a residue swap approach, substitution of RhoA Val 43 with an Ile was found to significantly promote basal nucleotide exchange activity and enhance GTP-loading in cells. Substitution of Val 43 with an Ile in RhoB negatively affected nucleotide exchange in vitro. Substitution of RhoC Ile 43 with a Val increased GEF-catalyzed exchange in vitro. In addition, RhoC-I43V was more efficacious at driving ovarian cancer cell invasion through matrigrel than wild-type RhoC, RhoC-I43T, wild-type RhoA, RhoA-V43I or RhoA-V43T GTPases. These findings suggest that a divergence between RhoA/B and RhoC at residue 43 impacts basal and GEF-stimulated nucleotide exchange activity.
Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Proteína rhoB de Ligação ao GTP/metabolismo , Animais , Linhagem Celular Tumoral , Guanosina Trifosfato/metabolismo , Humanos , Camundongos , Células NIH 3T3 , Mutação Puntual , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Proteínas rho de Ligação ao GTP/química , Proteínas rho de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/química , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoB de Ligação ao GTP/química , Proteína rhoB de Ligação ao GTP/genética , Proteína de Ligação a GTP rhoCRESUMO
The purpose of this retrospective review is to evaluate the safety and efficacy of the bronchial blockers (BBs) used in thoracic anesthesia. We enrolled 302 patients who had a BB placed to achieve one-lung ventilation (OLV). Variables recorded from the anesthetic record included type of device used, type and side of surgery, specific indications for OLV, Mallampati score, route of intubation, and complications related to the use of BBs. The BBs used include the Arndt Wire-guided, Univent, Cohen Flexi-tip, Fogarty catheter, and Fuji. The majority of BBs placed were Arndt (n = 156) or Univent (n = 131). BBs were used significantly more often in thoracoscopic procedures than in thoracotomies (P < 0.01). Of the 251 patients, 216 (86%) had a Mallampati score of I/II and 35 (14%) had a score of III/IV. There were no identified complications related to BBs. In summary, BBs can be safely used to achieve OLV and offer advantages for OLV in specific situations.
