The Role of Government-Funded Assistance Programs on HIV Testing Among Poor U.S. Adults.

Government-funded assistance program enrollment may play an important role in the overall increase of HIV testing among low-income U.S. adults. We pooled data from the 2016-2018 National Health Interview Survey and limited analyses to respondents aged 18 to 64 years with incomes less than 100% of the U.S. poverty threshold (N = 9,497). The outcome of interest was ever testing for HIV. Prevalence ratios were used to assess the likelihood of ever testing for HIV and were adjusted for sociodemographic covariates including whether the respondent was a beneficiary of any government-funded assistance programs (e.g., Medicaid; job-placement/training/human services; or Temporary Assistance for Needy Families). After adjusting for significant sociodemographic covariates, government-funded assistance beneficiaries were significantly more likely to ever test for HIV (adjusted prevalence ratio = 1.3; 95% CI = [1.2, 1.4], p < .0001) than adults with incomes less than 100% of the U.S. poverty threshold who did not receive government assistance. Beneficiaries of government-funded assistance programs are more likely to test for HIV.

Unmet needs for HIV ancillary care services by healthcare coverage and Ryan White HIV/AIDS program assistance.

OBJECTIVE: To investigate unmet needs for HIV ancillary care services by healthcare coverage type and Ryan White HIV/AIDS Program (RWHAP) assistance among adults with HIV. DESIGN: We analyzed data using the 2017-2019 cycles of the CDC Medical Monitoring Project, an annual, cross-sectional study designed to produce nationally representative estimates of characteristics among adults with diagnosed HIV. METHODS: Unmet need was defined as needing, but not receiving, one or more HIV ancillary care services. We estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) using predicted marginal means to examine associations between healthcare coverage type and unmet needs for HIV ancillary care services, adjusting for age. Associations were stratified by receipt of RWHAP assistance. RESULTS: Unmet needs for HIV ancillary care services were highest among uninsured persons (58.7%) and lowest among those with private insurance living with at least 400% of the federal poverty level (FPL; 21.7%). Uninsured persons who received RWHAP assistance were less likely than those who did not receive RWHAP assistance to have unmet needs for HIV clinical support services (aPR: 0.21; 95% CI: 0.16-0.28) and other medical services (aPR: 0.75; 95% CI: 0.59-0.96), but not subsistence services (aPR: 0.97; 95% CI: 0.74-1.27). Unmet needs for other medical services and subsistence services did not differ by RWHAP assistance among those with Medicaid, Medicare, or other healthcare coverage. CONCLUSIONS: RWHAP helped reduce some needs for uninsured persons. However, with growing socioeconomic inequities following the coronavirus disease 2019 pandemic, expanding access to needed services for all people with HIV could improve key outcomes.

Human genetic variants disrupt RGS14 nuclear shuttling and regulation of LTP in hippocampal neurons.

The human genome contains vast genetic diversity as naturally occurring coding variants, yet the impact of these variants on protein function and physiology is poorly understood. RGS14 is a multifunctional signaling protein that suppresses synaptic plasticity in dendritic spines of hippocampal neurons. RGS14 also is a nucleocytoplasmic shuttling protein, suggesting that balanced nuclear import/export and dendritic spine localization are essential for RGS14 functions. We identified genetic variants L505R (LR) and R507Q (RQ) located within the nuclear export sequence (NES) of human RGS14. Here we report that RGS14 encoding LR or RQ profoundly impacts protein functions in hippocampal neurons. RGS14 membrane localization is regulated by binding Gαi-GDP, whereas RGS14 nuclear export is regulated by Exportin 1 (XPO1). Remarkably, LR and RQ variants disrupt RGS14 binding to Gαi1-GDP and XPO1, nucleocytoplasmic equilibrium, and capacity to inhibit long-term potentiation (LTP). Variant LR accumulates irreversibly in the nucleus, preventing RGS14 binding to Gαi1, localization to dendritic spines, and inhibitory actions on LTP induction, while variant RQ exhibits a mixed phenotype. When introduced into mice by CRISPR/Cas9, RGS14-LR protein expression was detected predominantly in the nuclei of neurons within hippocampus, central amygdala, piriform cortex, and striatum, brain regions associated with learning and synaptic plasticity. Whereas mice completely lacking RGS14 exhibit enhanced spatial learning, mice carrying variant LR exhibit normal spatial learning, suggesting that RGS14 may have distinct functions in the nucleus independent from those in dendrites and spines. These findings show that naturally occurring genetic variants can profoundly alter normal protein function, impacting physiology in unexpected ways.

Disability among adults with diagnosed HIV in the United States, 2017.

In the United States, one in four adults is living with a disability. Age-related changes, disease-related pathology and treatments can place a person with HIV at risk for a disability. We analyzed nationally representative data to describe disability status among adults ≥18 years with diagnosed HIV in the United States and Puerto Rico by demographic characteristics, health behaviors, quality of care, clinical outcomes and mental health status. We reported weighted percentages and prevalence ratios with predicted marginal means to evaluate significant differences between groups (P < .05). Overall, 44.5% reported any disability; the most frequently reported disabilities were related to mobility (24.8%) and cognition (23.9%). Persons who lived in households at or below the poverty level or who experienced homelessness in the last 12 months reported a higher prevalence of any disability than persons who were not poor or not homeless (60.2% vs. 33.4% and 61.8% vs. 42.8%, respectively). Prevalence of depression and anxiety was higher among persons with any disability compared with those with no disability (32.8% and 26.6% versus 10.1% and 7.0%, respectively). Enhancing support from clinicians and ancillary providers may help optimize long-term health outcomes among HIV-positive persons with disabilities.

Depression Prevalence, Antidepressant Treatment Status, and Association with Sustained HIV Viral Suppression Among Adults Living with HIV in Care in the United States, 2009-2014.

Previous research indicates a high burden of depression among adults living with HIV and an association between depression and poor HIV clinical outcomes. National estimates of diagnosed depression, depression treatment status, and association with HIV clinical outcomes are lacking. We used 2009-2014 data from the Medical Monitoring Project to estimate diagnosed depression, antidepressant treatment status, and associations with sustained viral suppression (all viral loads in past year < 200 copies/mL). Data were obtained through interview and medical record abstraction and were weighted to account for unequal selection probabilities and non-response. Of adults receiving HIV medical care in the U.S. and prescribed ART, 27% (95% confidence interval [CI] 25-29%) had diagnosed depression during the surveillance period; the majority (65%) were prescribed antidepressants. The percentage with sustained viral suppression was highest among those without depression (72%, CI 71-73%) and lowest among those with untreated depression (66%, CI 64-69%). Compared to those without depression, those with a depression diagnosis were less likely to achieve sustained viral suppression (aPR 0.95, CI 0.93-0.97); this association held for persons with treated depression compared to no depression (aPR 0.96, CI 0.94-0.99) and untreated depression compared to no depression (aPR 0.92, CI 0.89-0.96). The burden of depression among adults living with HIV in care is high. While in our study depression was only minimally associated with a lower prevalence of sustained viral suppression, diagnosing and treating depression in persons living with HIV remains crucial in order to improve mental health and avoid other poor health outcomes.

A novel angiotensin-I converting enzyme inhibitory peptide derived from the glutelin of vinegar soaked black soybean and its antihypertensive effect in spontaneously hypertensive rats.

Vinegar soaked black soybean is a traditional Chinese food widely used for the treatment of hypertension. While its pharmacodynamic substance was not fully unveiled. It contained abundant glutelin, thus the purpose of this study was to obtain potent antihypertensive peptides from vinegar soaked black soybean. Black soybean was soaked with vinegar and then glutelin was first catalyzed by alcalase. Ultrafiltration, ion exchange chromatography and reversed-phase high performance liquid chromatography were sequentially applied to separate and purify the angiotensin-I converting enzyme (ACE) inhibitory peptides from glutelin hydrolysates. As a result, the fraction L1-4 with the highest ACE inhibitory activity (83.41%) at the final concentration of 0.01 mg/ml was obtained and five peptides were then identified. These peptides were further optimized by virtual screening combining with in silico proteolysis. Finally, a novel tetrapeptide Phe-Gly-Ser-Phe (FGSF) was obtained. FGSF exhibited high in vitro ACE inhibitory activity (IC50 = 117.11 µM) and in vivo hypotensive effect which maximally reduced systolic blood pressure of 21.95 mmHg at 20 mg/kg body weight in spontaneously hypertensive rats. Our study demonstrated that FGSF derived from vinegar soaked black soybean might be used as a promising ingredient for pharmaceuticals against hypertension and its related diseases.

Non-persistence to antiretroviral therapy among adults receiving HIV medical care in the United States.

Not taking medicine over a specific period of time-non-persistence to antiretroviral therapy (ART)-may be associated with higher HIV-viral load. However, national estimates of non-persistence among U.S. HIV patients are lacking. We examined the association between non-persistence and various factors, including sustained HIV-viral suppression (VS) stratified by adherence, and assessed reasons for non-persistence using Medical Monitoring Project (MMP) data. MMP conducts clinical and behavioral surveillance among cross-sectional representative samples of adults receiving HIV care in the U.S. We analyzed weighted MMP interview and medical record abstraction data collected between 6/2011-5/2015 from 18,423 patients self-reporting ART use. We defined non-persistence as a self-initiated decision to not take ART for ≥2 consecutive days in the past 12-months, non-adherence as missing ≥1 ART dose during the past 3-days and sustained VS as all HIV-viral loads documented in medical record during the past 12-months as undetectable or <200 copies/mL. We used Rao-Scott chi-square tests to examine the association between non-persistence and sociodemographic, behavioral, clinical, and medication-related factors. We examined the association between non-persistence and sustained VS, stratified by adherence, and present prevalence ratios (PRs) with 95% confidence intervals (CIs). Reasons for non-persistence were assessed. Overall, 7% of patients reported non-persistence. Drug use, depression and medication side effects were associated with non-persistence (P < 0.01). Non-persistence was associated with the lack of sustained VS (PR: .66, CI:63-.70); this association did not differ by adherence level. However, VS was lower among the non-persistent/adherent compared with the persistent/non-adherent [51% (CI:47-54) versus 61% (CI:36-46), P < 0.01]. The most prevalent reason for non-persistence was treatment fatigue (38%). Though few persons in HIV care reported non-persistence, our findings suggest that non-persistence is associated with lack of sustained VS, regardless of adherence. Routine screening for non-persistence during clinical appointments and counseling for those at risk for non-persistence may help improve clinical outcomes.

Cell-type specific role of the RNA-binding protein, NONO, in the DNA double-strand break response in the mouse testes.

The tandem RNA recognition motif protein, NONO, was previously identified as a candidate DNA double-strand break (DSB) repair factor in a biochemical screen for proteins with end-joining stimulatory activity. Subsequent work showed that NONO and its binding partner, SFPQ, have many of the properties expected for bona fide repair factors in cell-based assays. Their contribution to the DNA damage response in intact tissue in vivo has not, however, been demonstrated. Here we compare DNA damage sensitivity in the testes of wild-type mice versus mice bearing a null allele of the NONO homologue (Nono gt). In wild-type mice, NONO protein was present in Sertoli, peritubular myoid, and interstitial cells, with an increase in expression following induction of DNA damage. As expected for the product of an X-linked gene, NONO was not detected in germ cells. The Nono gt/0 mice had at most a mild testis developmental phenotype in the absence of genotoxic stress. However, following irradiation at sublethal, 2-4 Gy doses, Nono gt/0 mice displayed a number of indicators of radiosensitivity as compared to their wild-type counterparts. These included higher levels of persistent DSB repair foci, increased numbers of apoptotic cells in the seminiferous tubules, and partial degeneration of the blood-testis barrier. There was also an almost complete loss of germ cells at later times following irradiation, evidently arising as an indirect effect reflecting loss of stromal support. Results demonstrate a role for NONO protein in protection against direct and indirect biological effects of ionizing radiation in the whole animal.

Double-strand break repair deficiency in NONO knockout murine embryonic fibroblasts and compensation by spontaneous upregulation of the PSPC1 paralog.

NONO, SFPQ and PSPC1 make up a family of proteins with diverse roles in transcription, RNA processing and DNA double-strand break (DSB) repair. To understand long-term effects of loss of NONO, we characterized murine embryonic fibroblasts (MEFs) from knockout mice. In the absence of genotoxic stress, wild-type and mutant MEFs showed similar growth rates and cell cycle distributions, and the mutants were only mildly radiosensitive. Further investigation showed that NONO deficiency led to upregulation of PSPC1, which replaced NONO in a stable complex with SFPQ. Knockdown of PSPC1 in a NONO-deficient background led to severe radiosensitivity and delayed resolution of DSB repair foci. The DNA-dependent protein kinase (DNA-PK) inhibitor, NU7741, sensitized wild-type and singly deficient MEFs, but had no additional effect on doubly deficient cells, suggesting that NONO/PSPC1 and DNA-PK function in the same pathway. We tested whether NONO and PSPC1 might also affect repair indirectly by influencing mRNA levels for other DSB repair genes. Of 12 genes tested, none were downregulated, and several were upregulated. Thus, NONO or related proteins are critical for DSB repair, NONO and PSPC1 are functional homologs with partially interchangeable functions and a compensatory response involving PSPC1 blunts the effect of NONO deficiency.

The mRNA-binding protein Zfp36 is upregulated by ß-adrenergic stimulation and represses IL-6 production in 3T3-L1 adipocytes.

Obesity produces a chronic inflammatory state that contributes to the development of diabetes and atherosclerosis. In obese humans, fat depot adipocytes and macrophages produce inflammatory cytokines and other factors which exert unfavorable local and systemic immune responses. The expression of many cytokines is modulated at the post-transcriptional level by mRNA-binding proteins which recognize AU-rich elements (AREs) in the 3'-untranslated regions (3'-UTR) of these transcripts. One such protein, zinc finger protein 36 (Zfp36), is known to destabilize target mRNAs leading to decreased cytokine expression. Few regulators of Zfp36 expression in adipocytes have been described and mRNA targets of Zfp36 in adipocytes are largely unknown. We found that macrophage-derived inflammatory stimuli enhanced endogenous Zfp36 expression in 3T3-L1 adipocytes. Furthermore, the ß-adrenergic receptor agonist isoproterenol (Iso) and the glucocorticoid dexamethasone (Dex) each enhanced Zfp36 expression in adipocytes, the former most likely via a cyclic adenosine monophosphate (cAMP)-dependent pathway. By contrast, Zfp36 expression in murine macrophages (RAW 264.7) was not enhanced by exposure to Dex but was stimulated by retinoic acid (RA). Zfp36 inhibited basal and lipopolysaccharide (LPS)-stimulated interleukin-6 (IL-6) expression in adipocytes. These data reveal important and cell type-specific modulators of Zfp36 expression in adipocytes and macrophages and identify Zfp36 as a potent repressor of adipocyte-derived IL-6. Furthermore, this work identifies new factors that stimulate adipocyte Zfp36 expression that are neither classically inflammatory nor mitogenic. Upregulating an mRNA-binding protein for therapeutic purposes may provide a novel mechanistic approach with which to treat diverse inflammatory disorders including common conditions associated with obesity.

Intercalation of XR5944 with the estrogen response element is modulated by the tri-nucleotide spacer sequence between half-sites.

DNA-intercalating molecules can impair DNA replication, DNA repair, and gene transcription. We previously demonstrated that XR5944, a DNA bis-intercalator, specifically blocks binding of estrogen receptor-α (ERα) to the consensus estrogen response element (ERE). The consensus ERE sequence is AGGTCAnnnTGACCT, where nnn is known as the tri-nucleotide spacer. Recent work has shown that the tri-nucleotide spacer can modulate ERα-ERE binding affinity and ligand-mediated transcriptional responses. To further understand the mechanism by which XR5944 inhibits ERα-ERE binding, we tested its ability to interact with consensus EREs with variable tri-nucleotide spacer sequences and with natural but non-consensus ERE sequences using one dimensional nuclear magnetic resonance (1D (1)H NMR) titration studies. We found that the tri-nucleotide spacer sequence significantly modulates the binding of XR5944 to EREs. Of the sequences that were tested, EREs with CGG and AGG spacers showed the best binding specificity with XR5944, while those spaced with TTT demonstrated the least specific binding. The binding stoichiometry of XR5944 with EREs was 2:1, which can explain why the spacer influences the drug-DNA interaction; each XR5944 spans four nucleotides (including portions of the spacer) when intercalating with DNA. To validate our NMR results, we conducted functional studies using reporter constructs containing consensus EREs with tri-nucleotide spacers CGG, CTG, and TTT. Results of reporter assays in MCF-7 cells indicated that XR5944 was significantly more potent in inhibiting the activity of CGG- than TTT-spaced EREs, consistent with our NMR results. Taken together, these findings predict that the anti-estrogenic effects of XR5944 will depend not only on ERE half-site composition but also on the tri-nucleotide spacer sequence of EREs located in the promoters of estrogen-responsive genes.

Activation of the regulator of G protein signaling 14-Gαi1-GDP signaling complex is regulated by resistance to inhibitors of cholinesterase-8A.

RGS14 is a brain scaffolding protein that integrates G protein and MAP kinase signaling pathways. Like other RGS proteins, RGS14 is a GTPase activating protein (GAP) that terminates Gαi/o signaling. Unlike other RGS proteins, RGS14 also contains a G protein regulatory (also known as GoLoco) domain that binds Gαi1/3-GDP in cells and in vitro. Here we report that Ric-8A, a nonreceptor guanine nucleotide exchange factor (GEF), functionally interacts with the RGS14-Gαi1-GDP signaling complex to regulate its activation state. RGS14 and Ric-8A are recruited from the cytosol to the plasma membrane in the presence of coexpressed Gαi1 in cells, suggesting formation of a functional protein complex with Gαi1. Consistent with this idea, Ric-8A stimulates dissociation of the RGS14-Gαi1-GDP complex in cells and in vitro using purified proteins. Purified Ric-8A stimulates dissociation of the RGS14-Gαi1-GDP complex to form a stable Ric-8A-Gαi complex in the absence of GTP. In the presence of an activating nucleotide, Ric-8A interacts with the RGS14-Gαi1-GDP complex to stimulate both the steady-state GTPase activity of Gαi1 and binding of GTP to Gαi1. However, sufficiently high concentrations of RGS14 competitively reverse these stimulatory effects of Ric-8A on Gαi1 nucleotide binding and GTPase activity. This observation correlates with findings that show RGS14 and Ric-8A share an overlapping binding region within the last 11 amino acids of Gαi1. As further evidence that these proteins are functionally linked, native RGS14 and Ric-8A coexist within the same hippocampal neurons. These findings demonstrate that RGS14 is a newly appreciated integrator of unconventional Ric-8A and Gαi1 signaling.

The tri-nucleotide spacer sequence between estrogen response element half-sites is conserved and modulates ERalpha-mediated transcriptional responses.

The estrogen response element (ERE) consensus sequence is AGGTCAnnnTGACCT, where nnn is known as the tri-nucleotide spacer sequence. Studying 1017 high-confidence ERalpha-bound loci, we found that genomic EREs are enriched for spacers composed of C(A/T)G, suggesting that the spacer may influence receptor binding and transcriptional responses. We designed consensus EREs containing variable spacer sequences and compared ERalpha binding in gel shift assays and enhancer function in reporter assays. We found that ERalpha-ERE binding affinity is modulated by the tri-nucleotide spacer sequence and is favored by spacer sequences of CTG>GCC>TTT. Similarly, luciferase reporter assays indicated that the estrogen-stimulated transcriptional response is modulated by the spacer and parallels the gel shift data: CTG>GCC>TTT. Reporter assays demonstrated that the spacer sequence also modulates the sensitivity of EREs to repression engendered by the receptor antagonist hydroxytamoxifen. These experiments indicate that the sequence of the tri-nucleotide spacer is non-random at receptor-bound genomic loci, influences ERalpha-DNA-binding affinity, and modulates transactivation potential of the receptor-ligand-DNA complex. This work has implications for understanding which genomic EREs are targeted by ERalpha, should improve computational prediction of functional EREs within genomic sequences, and describes novel sequence determinants of the estrogen response.

Location analysis for the estrogen receptor-alpha reveals binding to diverse ERE sequences and widespread binding within repetitive DNA elements.

Location analysis for estrogen receptor-alpha (ERalpha)-bound cis-regulatory elements was determined in MCF7 cells using chromatin immunoprecipitation (ChIP)-on-chip. Here, we present the estrogen response element (ERE) sequences that were identified at ERalpha-bound loci and quantify the incidence of ERE sequences under two stringencies of detection: <10% and 10-20% nucleotide deviation from the canonical ERE sequence. We demonstrate that approximately 50% of all ERalpha-bound loci do not have a discernable ERE and show that most ERalpha-bound EREs are not perfect consensus EREs. Approximately one-third of all ERalpha-bound ERE sequences reside within repetitive DNA sequences, most commonly of the AluS family. In addition, the 3-bp spacer between the inverted ERE half-sites, rather than being random nucleotides, is C(A/T)G-enriched at bona fide receptor targets. Diverse ERalpha-bound loci were validated using electrophoretic mobility shift assay and ChIP-polymerase chain reaction (PCR). The functional significance of receptor-bound loci was demonstrated using luciferase reporter assays which proved that repetitive element ERE sequences contribute to enhancer function. ChIP-PCR demonstrated estrogen-dependent recruitment of the coactivator SRC3 to these loci in vivo. Our data demonstrate that ERalpha binds to widely variant EREs with less sequence specificity than had previously been suspected and that binding at repetitive and nonrepetitive genomic targets is favored by specific trinucleotide spacers.

RGS14 is a multifunctional scaffold that integrates G protein and Ras/Raf MAPkinase signalling pathways.

MAPkinase signalling is essential for cell growth, differentiation and cell physiology. G proteins and tyrosine kinase receptors each modulate MAPkinase signalling through distinct pathways. We report here that RGS14 is an integrator of G protein and MAPKinase signalling pathways. RGS14 contains a GPR/GoLoco (GL) domain that forms a stable complex with inactive Gialpha1/3-GDP, and a tandem (R1, R2) Ras binding domain (RBD). We find that RGS14 binds and regulates the subcellular localization and activities of H-Ras and Raf kinases in cells. Activated H-Ras binds RGS14 at the R1 RBD to form a stable complex at cell membranes. RGS14 also co-localizes with and forms a complex with Raf kinases in cells. The regulatory region of Raf-1 binds the RBD region of RGS14, and H-Ras and Raf each facilitate one another's binding to RGS14. RGS14 selectively inhibits PDGF-, but not EGF- or serum-stimulated Erk phosphorylation. This inhibition is dependent on H-Ras binding to RGS14 and is reversed by co-expression of Gialpha1, which binds and recruits RGS14 to the plasma membrane. Gialpha1 binding to RGS14 inhibits Raf binding, indicating that Gialpha1 and Raf binding to RGS14 are mutually exclusive. Taken together, these findings indicate that RGS14 is a newly appreciated integrator of G protein and Ras/Raf signalling pathways.

Selective interactions between Gi alpha1 and Gi alpha3 and the GoLoco/GPR domain of RGS14 influence its dynamic subcellular localization.

RGS14 is a multifunctional protein that contains an RGS domain, which binds active Gi/o alpha-GTP, a GoLoco/GPR domain, which binds inactive Gi alpha-GDP, and a tandem Rap1/2 binding domain (RBD). Studies were initiated to determine the roles of these domains and their interactions with Gi alpha on RGS14 subcellular localization. We report that RGS14 dynamic subcellular localization in HeLa cells depends on distinct domains and selective interactions with preferred Gi alpha isoforms. RGS14 shuttles rapidly between the nucleus and cytoplasm, and associates with centrosomes during interphase and mitosis. RGS14 localization to the nucleus depends on the RGS and RBD domains, its translocation out of the nucleus depends on the GoLoco/GPR domain, and its localization to centrosomes depends on the RBD domain. Gi alpha subunits (Gi alpha1, 2 and 3) localize predominantly at the plasma membrane. RGS14 binds directly to inactive and active forms of Gi alpha1 and Gi alpha3, but not Gi alpha2, both as a purified protein and when recovered from cells. RGS14 localizes predominantly at the plasma membrane in cells with inactive Gi alpha1 and Gi alpha3, but not Gi alpha2, whereas less RGS14 associates with active Gi alpha1/3 at the plasma membrane. RGS14 binding to inactive, but not active Gi alpha1/3 also prevents association with centrosomes or nuclear localization. Removal or functional inactivation of the GoLoco/GPR domain causes RGS14 to accumulate at centrosomes and in the nucleus, but renders it insensitive to recruitment to the plasma membrane by Gi alpha1/3. These findings highlight the importance of the GoLoco/GPR domain and its interactions with Gi alpha1/3 in determining RGS14 subcellular localization and linked functions.

Human aurora-B binds to a proteasome alpha-subunit HC8 and undergoes degradation in a proteasome-dependent manner.

Human Aurora/Ipl1-related kinase 2 (Aurora-B) is a key regulator of mitosis. Here human proteasome alpha-subunit C8 (HC8) was identified to interact with the Aurora-B by yeast two-hybrid screen. This finding was confirmed by GST pull-down assays and immunoprecipitation experiments. The Aurora-B protein level increased in HeLa cells cultured with proteasome inhibitor ALLN. Our data suggest that Aurora-B might undergo degradation by binding to HC8 in a proteasome-dependent manner during mitosis.