The Interplay between Protein L-Isoaspartyl Methyltransferase Activity and Insulin-Like Signaling to Extend Lifespan in Caenorhabditis elegans

The protein L-isoaspartyl-O-methyltransferase functions to initiate the repair of isomerized aspartyl and asparaginyl residues that spontaneously accumulate with age in a variety of organisms. Caenorhabditis elegans nematodes lacking the pcm-1 gene encoding this enzyme display a normal lifespan and phenotype under standard laboratory growth conditions. However, significant defects in development, egg laying, dauer survival, and autophagy have been observed in pcm-1 mutant nematodes when deprived of food and when exposed to oxidative stress. Interestingly, overexpression of this repair enzyme in both Drosophila and C. elegans extends adult lifespan under thermal stress. In this work, we show the involvement of the insulin/insulin-like growth factor-1 signaling (IIS) pathway in PCM-1-dependent lifespan extension in C. elegans. We demonstrate that reducing the levels of the DAF-16 downstream transcriptional effector of the IIS pathway by RNA interference reduces the lifespan extension resulting from PCM-1 overexpression. Using quantitative real-time PCR analysis, we show the up-regulation of DAF-16-dependent stress response genes in the PCM-1 overexpressor animals compared to wild-type and pcm-1 mutant nematodes under mild thermal stress conditions. Additionally, similar to other long-lived C. elegans mutants in the IIS pathway, including daf-2 and age-1 mutants, PCM-1 overexpressor adult animals display increased resistance to severe thermal stress, whereas pcm-1 mutant animals survive less long under these conditions. Although we observe a higher accumulation of damaged proteins in pcm-1 mutant nematodes, the basal level of isoaspartyl residues detected in wild-type animals was not reduced by PCM-1 overexpression. Our results support a signaling role for the protein L-isoaspartyl methyltransferase in lifespan extension that involves the IIS pathway, but that may be independent of its function in overall protein repair

Thinking about Race: The Salience of Racial Identity at Two- and Four-Year Colleges and the Climate for Diversity

Racial identity salience is an important component of identity development that is associated with a number of educational outcomes. Using the Diverse Learning Environments Survey, this study identifies precollege and college experiences that contribute to a heightened salience of racial identity, and its relationship to perceptions of campus climate

Standing on the shoulders of a giant: The legacy of Robert M. Sellers

Robert M. Sellers, PhD, most known for his influential and highly cited Multidimensional Model of Racial Identity (MMRI), is one of the most prolific and foundational Black scholars in psychology. From racial identity theory development and measurement to conceptual and methodological innovations in studying the lived experiences of Black people, Sellers' scholarship centers on the lives of Black communities. Sellers' mentorship and contributions to the professional development of scholars and professionals of color have supported and catalyzed new intergenerational knowledge building by these scholars, ensuring a perpetuating and far-reaching legacy in psychology. In this article, we: (a) celebrate Sellers' enduring contribution to the racial identity literature and its profound impact on psychology as a discipline as well as numerous subfields of psychology, (b) outline his contributions to the racial socialization literature, (c) describe methodological innovations in racial identity and racial socialization research advanced through his scholarship, and (d) summarize his contributions in professional development and mentorship and his leadership roles. Sellers' scholarly contributions and mentorship have transformed the discipline of psychology and the social sciences broadly speaking, making him one of the most influential psychologists in the modern era. (PsycInfo Database Record (c) 2023 APA, all rights reserved)