Mitochondrial-derived compartments facilitate cellular adaptation to amino acid stress

Amino acids are essential building blocks of life. However, increasing evidence suggests that elevated amino acids cause cellular toxicity associated with numerous metabolic disorders. How cells cope with elevated amino acids remains poorly understood. Here, we show that a previously identified cellular structure, the mitochondrial-derived compartment (MDC), functions to protect cells from amino acid stress. In response to amino acid elevation, MDCs are generated from mitochondria, where they selectively sequester and deplete SLC25A nutrient carriers and their associated import receptor Tom70 from the organelle. Generation of MDCs promotes amino acid catabolism, and their formation occurs simultaneously with transporter removal at the plasma membrane via the multivesicular body (MVB) pathway. The combined loss of vacuolar amino acid storage, MVBs, and MDCs renders cells sensitive to high amino acid stress. Thus, we propose that MDCs operate as part of a coordinated cell network that facilitates amino acid homeostasis through post-translational nutrient transporter remodeling

The fraternity of female friendly societies

In this chapter, the structured reciprocity of female friendly societies, even those with overt patrons, is presented as a categorization which is also applicable to men’s societies. The first part addresses the notion of independence, then the focus is on the financial aspect of the Southill Female Friendly Society, SFFS, which existed between 1844 and 1948 for women of that Bedfordshire village in England who were of ‘a good and honest character’, in good health and aged between 14 and 45 when they joined. Members had few other opportunities to reduce the risks associated with illness other than accept the uneven reciprocity of the SFFS. The patrons may also have seen the SFFS as an investment opportunity. Then the attractions of Southill, with its healthy housing and relatively liberal interpretation of relief legislation, are presented as evidence of another important attribute of successful friendly societies, their centrality to social networking. Next is considered how far mutuality and philanthropy were interwoven within the SFFS and elsewhere. An assessment of the roles of civil engagement and moral regulation within friendly societies follows and the final section suggests that a notion of fraternity which emphasizes flexible reciprocity can net together both vast international brotherhoods and tiny village societies in a way which illuminate understandings of nineteenth-century society