The katanin A-subunits KATNA1 and KATNAL1 act co-operatively in mammalian meiosis and spermiogenesis to achieve male fertility.

Katanins, a class of microtubule-severing enzymes, are potent M-phase regulators in oocytes and somatic cells. How the complex and evolutionarily crucial, male mammalian meiotic spindle is sculpted remains unknown. Here, using multiple single and double gene knockout mice, we reveal that the canonical katanin A-subunit KATNA1 and its close paralogue KATNAL1 together execute multiple aspects of meiosis. We show KATNA1 and KATNAL1 collectively regulate the male meiotic spindle, cytokinesis and midbody abscission, in addition to diverse spermatid remodelling events, including Golgi organisation, and acrosome and manchette formation. We also define KATNAL1-specific roles in sperm flagellum development, manchette regulation and sperm-epithelial disengagement. Finally, using proteomic approaches, we define the KATNA1, KATNAL1 and KATNB1 mammalian testis interactome, which includes a network of cytoskeletal and vesicle trafficking proteins. Collectively, we reveal that the presence of multiple katanin A-subunit paralogs in mammalian spermatogenesis allows for 'customised cutting' via neofunctionalisation and protective buffering via gene redundancy.

Older adults' experiences using Alexa.

The number of adults in the United States age 65 and older is expected to increase to 81 million in 2040 and 95 million in 2060. Voice-activated personal assistants (VAPAs), such as Amazon's Alexa, have the potential to ensure that older adults can successfully age in place using smart home technology to support health, wellness, social engagement, and daily functioning at home. To further explore this potential, twelve home-dwelling older adults aged 65 and older who had used the Amazon Alexa VAPA device for over six months were interviewed to learn about their perceptions and experiences with the use of the device and to gain insights into how this technology has shaped their aging experience. Findings suggest that the older adults did not fully understand the full spectrum of functionality and features of the Alexa device, as they received relatively little initial and ongoing training and support in using it. Participants enjoyed using the Alexa device for selective non-essential features and functions that were more convenient to use on the Alexa device than through alternative methods, but they did not see the use of the Alexa device as essential to their successfully aging in place. CCS CONCEPTS • Accessibility • Ubiquitous and mobile computing • Human-computer interaction.