CLINICAL GUIDELINES FOR DIAGNOSIS, TREATMENT AND MONITORING OF PATIENTS WITH NON-INVASIVE BREAST CANCER

Rak dojke najčešća je maligna bolest u žena. Ranom dijagnostikom i sve uspješnijim liječenjem invazivnog raka dojke postignut je značajan pad mortaliteta, produljenje preživljenja i poboljšanje kvalitete života bolesnica. Postupak s neinvazivnim rakom dojke međutim povezan je s nekim dvojbama i sviješću o problemu predijagnosticiranja i pretjeranog liječenja nekih bolesnica. U tekstu koji slijedi multidisciplinarni tim stručnjaka donosi prve hrvatske smjernice čija je svrha standardizacija i optimalizacija kriterija i postupaka dijagnostike, liječenja i praćenja bolesnica s neinvazivnim rakom dojke u Republici Hrvatskoj.Breast cancer is the most common malignancy in women. Early diagnosis and more effective treatment of invasive breast cancer resulted in significant mortality reduction, improvement of survival and the quality of life of the patients. The management od non-invasive breast cancer, on the contrary, is still controversial and the problem of overdiagnosis and overtreatment of patients come to evidence. In the following text a multidisciplinary team of experts brings the first consensus guidelines aimed to standardize and optimize the criteria and management in diagnosis, treatment and monitoring of non-invasive breast cancer patients in the Republic of Croatia

Mechanisms of Generating Polyubiquitin Chains of Different Topology

Ubiquitination is an important post-translational process involving attachment of the ubiquitin molecule to lysine residue/s on a substrate protein or on another ubiquitin molecule, leading to the formation of protein mono-, multi- or polyubiquitination. Protein ubiquitination requires a cascade of three enzymes, where the interplay between different ubiquitin-conjugating and ubiquitin-ligase enzymes generates diverse ubiquitinated proteins topologies. Structurally diverse ubiquitin conjugates are recognized by specific proteins with ubiquitin-binding domains (UBDs) to target the substrate proteins of different pathways. The mechanism/s for generating the different ubiquitinated proteins topologies is not well understood. Here, we will discuss our current understanding of the mechanisms underpinning the generation of mono- or polyubiquitinated substrates. In addition, we will discuss how linkage-specific polyubiquitin chains through lysines-11, -48 or -63 are formed to target proteins to different fates by binding specific UBD proteins

Kliničke smjernice za dijagnostiku, liječenje i praćenje bolesnika s neinvazivnim rakom dojke [Clinical guidelines for diagnosis, treatment and monitoring of patients with non-invasive breast cancer]

Breast cancer is the most common malignancy in women. Early diagnosis and more effective treatment of invasive breast cancer resulted in significant mortality reduction, improvement of survival and the quality of life of the patients. The management od non-invasive breast cancer, on the contrary, is still controversial and the problem of overdiagnosis and overtreatment of patients come to evidence. In the following text a multidisciplinary team of experts brings the first consensus guidelines aimed to standardize and optimize the criteria and management in diagnosis, treatment and monitoring of non-invasive breast cancer patients in the Republic of Croatia

Molecular and structural insight into lysine selection on substrate and ubiquitin lysine 48 by the ubiquitin-conjugating enzyme Cdc34

The attachment of ubiquitin (Ub) to lysines on substrates or itself by ubiquitin-conjugating (E2) and ubiquitin ligase (E3) enzymes results in protein ubiquitination. Lysine selection is important for generating diverse substrate-Ub structures and targeting proteins to different fates; however, the mechanisms of lysine selection are not clearly understood. The positioning of lysine(s) toward the E2/E3 active site and residues proximal to lysines are critical in their selection. We investigated determinants of lysine specificity of the ubiquitin-conjugating enzyme Cdc34, toward substrate and Ub lysines. Evaluation of the relative importance of different residues positioned −2, −1, +1 and +2 toward ubiquitination of its substrate, Sic1, on lysine 50 showed that charged residues in the −1 and −2 positions negatively impact on ubiquitination. Modeling suggests that charged residues at these positions alter the native salt-bridge interactions in Ub and Cdc34, resulting in misplacement of Sic1 lysine 50 in the Cdc34 catalytic cleft. During polyubiquitination, Cdc34 showed a strong preference for Ub lysine 48 (K48), with lower activity towards lysine 11 (K11) and lysine 63 (K63). Mutating the −2, −1, +1 and +2 sites surrounding K11 and K63 to mimic those surrounding K48 did not improve their ubiquitination, indicating that further determinants are important for Ub K48 specificity. Modeling the ternary structure of acceptor Ub with the Cdc34~Ub complex as well as in vitro ubiquitination assays unveiled the importance of K6 and Q62 of acceptor Ub for Ub K48 polyubiquitination. These findings provide molecular and structural insight into substrate lysine and Ub K48 specificity by Cdc34