SummaryYeast prions require a core set of chaperone proteins including Sis1, Hsp70 and Hsp104 to generate new amyloid templates for stable propagation, yet emerging studies indicate that propagation of some prions requires additional chaperone activities, demonstrating chaperone specificity beyond the common amyloid requirements. To comprehensively assess such prion‐specific requirements for the propagation of the [URE 3] prion variant [URE 3‐1], we screened 12 yeast cytosolic J‐proteins, and here we report a novel role for the J‐protein Swa2/Aux1. Swa2 is the sole yeast homolog of the mammalian protein auxilin, which, like Swa2, functions in vesicle‐mediated endocytosis by disassembling the structural lattice formed by the protein clathrin. We found that, in addition to Sis1, [URE 3‐1] is specifically dependent upon Swa2, but not on any of the 11 other J‐proteins. Further, we show that [URE 3‐1] propagation requires both a functional J‐domain and the tetratricopeptide repeat (TPR) domain, but surprisingly does not require Swa2‐clathrin binding. Because the J‐domain of Swa2 can be replaced with the J‐domains of other proteins, our data strongly suggest that prion‐chaperone specificity arises from the Swa2 TPR domain and supports a model where Swa2 acts through Hsp70, most likely to provide additional access points for Hsp104 to promote prion template generation.

Yeast prions are protein-based genetic elements that propagate through cell populations via cytosolic transfer from mother to daughter cell. Molecular chaperone proteins including Hsp70, the Hsp40/J-protein Sis1, and Hsp104 are required for continued prion propagation, however the specific requirements of chaperone proteins differ for various prions. We recently reported that Swa2, the yeast homolog of the mammalian protein auxilin, is specifically required for the propagation of the prion [URE3].1 [URE3] propagation requires both a functional J-domain and the tetratricopeptide repeat (TPR) domain of Swa2, but does not require Swa2 clathrin binding. We concluded that the TPR domain determines the specificity of the genetic interaction between Swa2 and [URE3], and that this domain likely interacts with one or more proteins with a C-terminal EEVD motif. Here we extend that analysis to incorporate additional data that supports this hypothesis. We also present new data eliminating Hsp104 as the relevant Swa2 binding partner and discuss our findings in the context of other recent work involving Hsp90. Based on these findings, we propose a new model for Swa2's involvement in [URE3] propagation in which Swa2 and Hsp90 mediate the formation of a multi-protein complex that increases the number of sites available for Hsp104 disaggregation.

Endocannabinoid signaling depends upon the CB1 and CB2 cannabinoid receptors, their endogenous ligands anandamide and 2-arachidonoylglycerol, and intracellular proteins that mediate responses via the C-terminal and other intracellular receptor domains. The CB1 receptor regulates and is regulated by associated G proteins predominantly of the Gi/o subtypes, β-arrestins 1 and 2, and the cannabinoid receptor-interacting protein 1a (CRIP1a). Evidence for a physiological role for CRIP1a is emerging as data regarding the cellular localization and function of CRIP1a are generated. Here we summarize the neuronal distribution and role of CRIP1a in endocannabinoid signaling, as well as discuss investigations linking CRIP1a to development, vision and hearing sensory systems, hippocampus and seizure regulation, and psychiatric disorders including schizophrenia. We also examine the genetic and epigenetic association of CRIP1a within a variety of cancer subtypes. This review provides evidence upon which to base future investigations on the function of CRIP1a in health and disease.

Previous results from our laboratory assert that the yeast Hsp40 chaperone protein Swa2 is essential for the propagation of the prion [URE3] in a yeast population. Swa2 is the sole yeast homolog of mammalian protein auxilin, which functions in vesicle‐mediated endocytosis by disassembling the structural lattice formed by the protein clathrin. The objective of this study was to find the determinants of the specific genetic interaction between Swa2 and [URE3]. The primary method used in this study was complementation by plasmid‐shuffling in the budding yeast Saccharomyces cerevisiae. Summary of Results: Our investigation revealed that two regions of the Swa2 protein, the J‐domain and the tetratricopeptide repeat region (TPR) are both necessary and sufficient to maintain [URE3], but that the TPR domain is solely responsible for prion/chaperone specificity. While the function of the TPR domain in Swa2 is undetermined, TPR domains typically act as docking platforms for a variety of protein complexes. As such we propose that the Swa2 TPR domain either participates in a bipartite interaction with Hsp70, analogous to the C‐terminal domains of other yeast Hsp40s, or that the TPR domain mediates the formation of a ternary complex with another undetermined protein in [URE3] propagation. We expect that understanding the function of the Swa2 TPR domain will provide new insight into both J‐protein function and the complex mechanisms of prion propagation.This work was supported by a Single‐Investigator Cottrell College Science Award (Award #21010) from the Research Corporation for Science Advancement and by by the National Institute Of General Medical Sciences of the National Institutes of Health under Award Number R15GM110606.