An AMPKα2-specific phospho-switch controls lysosomal targeting for activation.

AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin complex 1 (mTORC1) are metabolic kinases that co-ordinate nutrient supply with cell growth. AMPK negatively regulates mTORC1, and mTORC1 reciprocally phosphorylates S345/7 in both AMPK α-isoforms. We report that genetic or torin1-induced loss of α2-S345 phosphorylation relieves suppression of AMPK signaling; however, the regulatory effect does not translate to α1-S347 in HEK293T or MEF cells. Dephosphorylation of α2-S345, but not α1-S347, transiently targets AMPK to lysosomes, a cellular site for activation by LKB1. By mass spectrometry, we find that α2-S345 is basally phosphorylated at 2.5-fold higher stoichiometry than α1-S347 in HEK293T cells and, unlike α1, phosphorylation is partially retained after prolonged mTORC1 inhibition. Loss of α2-S345 phosphorylation in endogenous AMPK fails to sustain growth of MEFs under amino acid starvation conditions. These findings uncover an α2-specific mechanism by which AMPK can be activated at lysosomes in the absence of changes in cellular energy.

An approach to functionally relevant clustering of the protein universe: Active site profile-based clustering of protein structures and sequences.

Protein function identification remains a significant problem. Solving this problem at the molecular functional level would allow mechanistic determinant identification-amino acids that distinguish details between functional families within a superfamily. Active site profiling was developed to identify mechanistic determinants. DASP and DASP2 were developed as tools to search sequence databases using active site profiling. Here, TuLIP (Two-Level Iterative clustering Process) is introduced as an iterative, divisive clustering process that utilizes active site profiling to separate structurally characterized superfamily members into functionally relevant clusters. Underlying TuLIP is the observation that functionally relevant families (curated by Structure-Function Linkage Database, SFLD) self-identify in DASP2 searches; clusters containing multiple functional families do not. Each TuLIP iteration produces candidate clusters, each evaluated to determine if it self-identifies using DASP2. If so, it is deemed a functionally relevant group. Divisive clustering continues until each structure is either a functionally relevant group member or a singlet. TuLIP is validated on enolase and glutathione transferase structures, superfamilies well-curated by SFLD. Correlation is strong; small numbers of structures prevent statistically significant analysis. TuLIP-identified enolase clusters are used in DASP2 GenBank searches to identify sequences sharing functional site features. Analysis shows a true positive rate of 96%, false negative rate of 4%, and maximum false positive rate of 4%. F-measure and performance analysis on the enolase search results and comparison to GEMMA and SCI-PHY demonstrate that TuLIP avoids the over-division problem of these methods. Mechanistic determinants for enolase families are evaluated and shown to correlate well with literature results.

Improvements in Interpersonal Functioning Following Interpersonal Psychotherapy (IPT) with Adolescents and their Association with Change in Depression.

BACKGROUND: This study adds to the body of evidence regarding the theoretical underpinnings of interpersonal psychotherapy and the mechanisms through which it impacts upon depression in adolescents. AIMS: The aims were to determine whether the interpersonal constructs proposed to underpin interpersonal psychotherapy do indeed change in response to this therapy and whether such changes are associated with changes in depression in young people. METHOD: Thirty-nine adolescents, aged 13-19 years, with a primary diagnosis of major depressive disorder, were randomly assigned in blocks to group or individual treatment. Assessments were conducted at pre and posttreatment, and 12-month follow-up. RESULTS: The results supported the hypotheses, with significant improvements in social skills, social functioning, and the quality of parent-adolescent relationships, and an increase in secure attachment style and decrease in insecure attachment style being evident following treatment. Benefits were maintained at 12-month follow-up. Adolescents who showed greater reductions in depressive symptoms over this period tended to also show greater improvement in parent reported social skills, quality of the parent-adolescent relationship, and attachment style from pretreatment to 12-month follow-up. CONCLUSIONS: The findings are consistent with the proposed underpinnings of interpersonal psychotherapy. Adolescents showed significant improvements in interpersonal functioning and changes in attachment style following treatment, and changes in social skills, parent-adolescent conflict and attachment style were associated with reductions in depression. As such, the results add to the body of knowledge regarding the construct validity of interpersonal psychotherapy as an intervention for depression in young people. Clinical implications and directions for future research are discussed.

Group versus individual interpersonal psychotherapy for depressed adolescents.

BACKGROUND: This study adds to the limited evidence concerning the benefits of Interpersonal Psychotherapy (IPT) with depressed adolescents. It evaluates the long-term effects of group versus individual delivery of this treatment approach. AIMS: To conduct a small-scale examination of the long-term efficacy of group versus individual delivery of IPT for depressed adolescents. METHOD: Thirty-nine adolescents, aged 13-19 years, with a primary diagnosis of Major Depressive Disorder, were randomly assigned in blocks to either group or individual delivery of IPT. Standardized clinical interview and questionnaire assessments were conducted at pre- and posttreatment, and 12-month follow-up. RESULTS: Intent-to-treat (ITT) analyses indicated significant improvements in depression, anxiety, youth-reported internalizing problems, and global functioning from pre- to posttreatment for those receiving IPT, with no significant differences in outcome between group and individual formats of delivery. Improvements were maintained at 12-month follow-up. Completer analyses also revealed significant and sustained improvements on these measures for those receiving IPT, with no differences in outcome between therapy formats for most measures. Individual IPT showed significantly greater improvements than group IPT in parent-reported internalizing problems for the completer but not the ITT analyses. CONCLUSIONS: Both individual and group formats of IPT offer promise in producing long-term benefits in the treatment of depression among adolescents.

Interpersonal factors associated with depression in adolescents: are these consistent with theories underpinning interpersonal psychotherapy?

The aim of this study was to investigate whether depressed adolescents differed from non-depressed adolescents in terms of constructs consistent with those that are proposed to underpin interpersonal psychotherapy. In particular, it was hypothesized that compared with non-depressed adolescents, depressed adolescents would demonstrate a greater number of negative life events associated with interpersonal loss and major life transitions, a more insecure attachment style and poorer communication skills, interpersonal relationships and social support. Thirty-one clinically diagnosed depressed adolescents were matched with 31 non-depressed adolescents on age, gender and socio-economic status. The 62 participants were aged between 12 and 19 years and comprised 18 male and 44 female adolescents. On a self-report questionnaire, depressed adolescents reported a greater number of negative interpersonal life events, a less secure attachment style and scored higher on all insecure attachment styles compared with the non-depressed adolescents. In addition, depressed adolescents demonstrated lower levels of social skill (on both adolescent and parent report), a poorer quality of relationship with parents (on both adolescent and parent report) and lower social competence (adolescent report only). Parents of depressed adolescents also reported more negative parental attitudes and behaviours towards their adolescent compared with parents of non-depressed adolescents. Thus, the results of this study are consistent with the constructs underlying interpersonal psychotherapy and suggest their usefulness in the assessment, conceptualization and treatment of adolescent depression. Clinical implications are discussed.