Trypanosomatid RACK1 Orthologs Show Functional Differences Associated with Translation Despite Similar Roles in Leishmania Pathogenesis

RACK1 proteins belong to the eukaryote WD40-repeat protein family and function as spatial regulators of multiple cellular events, including signaling pathways, the cell cycle and translation. For this latter role, structural and genetic studies indicate that RACK1 associates with the ribosome through two conserved positively charged amino acids in its first WD40 domain. Unlike RACK1s, including Trypanosoma brucei RACK1 (TbRACK1), only one of these two positively-charged residues is conserved in the first WD40 domain of the Leishmania major RACK1 ortholog, LACK. We compared virulence-attenuated LACK single copy (LACK/-) L. major, with L. major expressing either two LACK copies (LACK/LACK), or one copy each of LACK and TbRACK1 (LACK/TbRACK1), to evaluate the function of these structurally distinct RACK1 orthologs with respect to translation, viability at host temperatures and pathogenesis. Our results indicate that although the ribosome-binding residues are not fully conserved in LACK, both LACK and TbRACK1 co-sedimented with monosomes and polysomes in LACK/LACK and LACK/TbRACK1 L. major, respectively. LACK/LACK and LACK/TbRACK1 strains differed in their sensitivity to translation inhibitors implying that minor sequence differences between the RACK1 proteins can alter their functional properties. While biochemically distinguishable, both LACK/LACK and LACK/TbRACK1 lines were more tolerant of elevated temperatures, resistant to translation inhibitors, and displayed robust pathogenesis in vivo, contrasting to LACK/- parasites

Which breast cancer decisions remain non-compliant with guidelines despite the use of computerised decision support?

Despite multidisciplinary tumour boards (MTBs), non-compliance with clinical practice guidelines is still observed for breast cancer patients. Computerised clinical decision support systems (CDSSs) may improve the implementation of guidelines, but cases of non-compliance persist. OncoDoc2, a guideline-based decision support system, has been routinely used to remind MTB physicians of patient-specific recommended care plans. Non-compliant MTB decisions were analysed using a multivariate adjusted logistic regression model. Between 2007 and 2009, 1624 decisions for invasive breast cancers with a global non-compliance rate of 8.3% were analysed. Patient factors associated with non-compliance were age>80 years (odds ratio (OR): 7.7; 95% confidence interval (CI): 3.7-15.7) in pre-surgical decisions; microinvasive tumour (OR: 5.2; 95% CI: 1.5-17.5), surgical discovery of microinvasion in addition to a unique invasive tumour (OR: 4.2; 95% CI: 1.4-12.5), and prior neoadjuvant treatment (OR: 4.2; 95% CI: 1.1-15.1) in decisions with recommendation of re-excision; age<35 years (OR: 4.7; 95% CI: 1.9-11.4), positive hormonal receptors with human epidermal growth factor receptor 2 overexpression (OR: 15.7; 95% CI: 3.1-78.7), and the absence of prior axillary surgery (OR: 17.2; 95% CI: 5.1-58.1) in adjuvant decisions. Residual non-compliance despite the use of OncoDoc2 illustrates the need to question the clinical profiles where evidence is missing. These findings challenge the weaknesses of guideline content rather than the use of CDSSs