Amelioration of SARS-CoV-2 infection by ANO6 phospholipid scramblase inhibition.

As an enveloped virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delivers its viral genome into host cells via fusion of the viral and cell membranes. Here, we show that ANO6/TMEM16F-mediated cell surface exposure of phosphatidylserine is critical for SARS-CoV-2 entry and that ANO6-selective inhibitors are effective against SARS-CoV-2 infections. Application of the SARS-CoV-2 Spike pseudotyped virus (SARS2-PsV) evokes a cytosolic Ca2+ elevation and ANO6-dependent phosphatidylserine externalization in ACE2/TMPRSS2-positive mammalian cells. A high-throughput screening of drug-like chemical libraries identifies three different structural classes of chemicals showing ANO6 inhibitory effects. Among them, A6-001 displays the highest potency and ANO6 selectivity and it inhibits the single-round infection of SARS2-PsV in ACE2/TMPRSS2-positive HEK 293T cells. More importantly, A6-001 strongly inhibits authentic SARS-CoV-2-induced phosphatidylserine scrambling and SARS-CoV-2 viral replications in Vero, Calu-3, and primarily cultured human nasal epithelial cells. These results provide mechanistic insights into the viral entry process and offer a potential target for pharmacological intervention to protect against coronavirus disease 2019 (COVID-19).

Differential Correlations among Allergy Tests According to Indoor Allergens in Allergic Rhinitis.

OBJECTIVES: Several allergy tests are used for the diagnosis of allergic rhinitis; however, few studies have reported a direct comparison of the skin prick test (SPT), multiple allergen simultaneous test (MAST), and ImmunoCAP according to specific allergens. This study aimed to evaluate the correlations between each test and allergic rhinitis symptoms and to evaluate the correlations of the MAST and ImmunoCAP with the SPT for representative indoor allergens in Korea. METHODS: Electronic medical charts were retrospectively reviewed, and 698 patients with allergic rhinitis who had performed SPT, MAST, and ImmunoCAP were enrolled. Correlations between each allergy test for 4 representative indoor allergens and the symptoms of allergic rhinitis were analyzed. Agreements of the MAST and ImmunoCAP with the SPT were compared according to each allergen. RESULTS: The SPT showed higher correlations with allergic rhinitis symptoms for 4 indoor allergens (Dermatophagoides pteronyssinus, Dermatophagoides farinae, cat, and dog allergens) than the MAST or ImmunoCAP. In comparison between the MAST and SPT, the least correlation was observed for the dog allergen, whereas between the ImmunoCAP and SPT, the least correlation was observed for the cat allergen. The correlation between the ImmunoCAP and SPT was higher than that between the MAST and SPT for the dog allergen, whereas no significant differences were noted for other allergens. CONCLUSIONS: Overall, the SPT showed a higher correlation with allergic rhinitis symptoms than the MAST or ImmunoCAP for 4 indoor allergens. ImmunoCAP showed similar reactivity to MAST; however, it showed better positivity with dog allergen in patients who were reactive to the allergen in the SPT. Care should be taken while evaluating dog allergen sensitization using the MAST.

Effectiveness of cross-linked human acellular dermal matrix in primary and revision augmentation rhinoplasty.

BACKGROUND: Among the materials used for dorsal augmentation rhinoplasty (DAR), cross-linked human acellular dermal matrix (ADM) has been claimed for its low risk of infection and extrusion. The aim of this study was to compare the effectiveness of ADM in subjects undergoing primary versus revision dorsal augmentation rhinoplasties. METHODS: Using a retrospective cohort study design, the investigators enrolled a cohort set of DAR patients operated by a single surgeon during a 65-month interval. The predictor variable was the treatment group (primary or revision DAR). The main outcome variables were postoperative changes with regard to the degree of augmentation (ratio of the dorsal height [DH] and radix height [RH] to the nasal length) and patients' and surgeons' satisfaction with the aesthetic and functional results. Other study variables were grouped into the following categories: demographic, surgical, and pathological. Descriptive, uni-, and bivariate statistics were computed using P ≤ 0.05 as a cutoff value. RESULTS: The study cohort comprised 145 subjects (75.2% with primary DAR; 39.3% females) with a mean age of 30.7 ±â€¯9.4 years (range, 19-58). DAR was linked to the significant changes in DH and RH in both the treatment groups. Comparison of the two groups revealed that there was no significant difference in DH and RH between both the groups. Surgeons' and patients' satisfaction rates were comparable between the two surgery groups, neither of which experienced serious complications. Microscopic findings of the removed ADM showed abundant collagen tissue with newly formed vessels without signs of foreign body reaction. CONCLUSION: Despite significant differences in patient characteristics (age; number of osteotomy, tip plasty, and hump reduction surgeries), the results of this study suggest that ADM can be used in both primary and revision DAR, with minimal complications.

Association between diabetes mellitus and chronic rhinosinusitis with nasal polyps: A population-based cross-sectional study.

OBJECTIVE: To investigate the association between physician-diagnosed diabetes mellitus (DM) and chronic rhinosinusitis (CRS) phenotypes in a national population-based study. STUDY DESIGN: Retrospective cross-sectional study. SETTING: Population-based survey data were collected by the Korean National Health and Nutrition Survey between January 2008 and December 2012. PARTICIPANTS AND METHODS: A total of 34 670 participants aged over 19 years were enrolled in the Korea National Health and Nutrition Examination Surveys from 2008 to 2012. The relationship of CRS prevalence, with and without nasal polyps, with physician-diagnosed DM and non-DM were assessed. Differences in sinonasal symptoms between patients with and without DM were analysed in this cross-sectional study. RESULTS: A significant association was observed between DM and CRS with nasal polyps after adjustment for multiple variables. No substantial association was observed between DM and CRS without nasal polyps. Among patients with CRS, olfactory dysfunction for >3 months was significantly more frequent in the DM group than in the non-DM group. CONCLUSION: We demonstrated significant associations between DM and CRS with nasal polyps and olfactory dysfunction among patients with CRS in a large national clinical cohort study. The direct mechanism of the association between DM and CRS with nasal polyps should be further investigated to clarify the pathogenesis of CRS with nasal polyps.

Association between obesity and chronic rhinosinusitis with nasal polyps: a national population-based study.

OBJECTIVES: We performed a cross-sectional analysis of data from the nationwide Korea National Health and Nutrition Examination Survey to evaluate the association between obesity and chronic rhinosinusitis with nasal polyps (CRSwNP) or without nasal polyp (CRSsNP). DESIGN: Retrospective cross-sectional analysis of health survey data. SETTING: Voluntary survey of representative South Korean populations. PARTICIPANTS: In total, 32 384 individuals aged 19 years or older with available data on CRS and obesity were included. PRIMARY AND SECONDARY OUTCOME MEASURES: Diagnosis of CRSwNP or CRSsNP was performed by trained otolaryngologists through sinus endoscopy and surveys of medical history. General and central obesity was diagnosed using body mass index (BMI) and waist circumference (WC), respectively. METHODS: A multivariate logistic regression analysis was used to clarify the association between CRSwNP or CRSsNP and obesity according to BMI and WC. Non-obese individuals were recruited as controls. RESULTS: The prevalence of CRSwNP was higher in the general (OR, 1.438; 95% CI, 1.170 to 1.768; p<0.001) and central (OR, 1.251; 95% CI, 1.031 to 1.520; p=0.033) obesity groups than in the control group. Prevalence of CRSsNP was not correlated with obesity. In a logistic regression analysis, olfactory dysfunction (OR, 1.329; 95% CI, 1.137 to 1.553; p<0.001) and purulent discharge (OR, 1.383; 95% CI, 1.193 to 1.603; p<0.001) showed a higher incidence in the central obesity group than in the control group. CONCLUSIONS: We demonstrated an association between CRSwNP and general and central obesity. Further investigations on the mechanism underlying this correlation are necessary for an improved understanding of the pathogenesis of CRSwNP.

Elucidation of genomic organizations of transgenic soybean plants through de novo genome assembly with short paired-end reads.

Elucidation of the genomic organizations of transgene insertion sites is essential for the genetic studies of transgenic plants. Herein, we establish an analysis pipeline that identifies the transgene insertion sites as well as the presence of vector backbones, through de novo genome assembly with high-throughput sequencing data in two transgenic soybean lines, AtYUCCA6-#5 and 35S-UGT72E3/2-#7. Sequencing data of approximately 28× and 29× genome coverages for each line generated by high-throughput sequencing were de novo assembled. The databases generated from the de novo assembled sequences were used to search contigs that contained putative insertion sites and their flanking sequences (integration sites) of transgene fragments using transgenic vector sequences as queries. The predicted integration site sequences, which are located at three annotated genes that might regulate plant development or confer disease resistance, were then confirmed by local alignment against the soybean reference genome and PCR amplification. As results, we revealed the precise transgene-flanking sequences and sequence rearrangements at insertion sites in both the transgenic lines, as well as the aberrant insertion of a transgene fragment. Consequently, relative to experimental or enrichment technologies, our approach is straightforward and time-effective, providing an alternative method for the identification of insertion sites in transgenic plants.

HOS15 is a transcriptional corepressor of NPR1-mediated gene activation of plant immunity.

Transcriptional regulation is a complex and pivotal process in living cells. HOS15 is a transcriptional corepressor. Although transcriptional repressors generally have been associated with inactive genes, increasing evidence indicates that, through poorly understood mechanisms, transcriptional corepressors also associate with actively transcribed genes. Here, we show that HOS15 is the substrate receptor for an SCF/CUL1 E3 ubiquitin ligase complex (SCFHOS15) that negatively regulates plant immunity by destabilizing transcriptional activation complexes containing NPR1 and associated transcriptional activators. In unchallenged conditions, HOS15 continuously eliminates NPR1 to prevent inappropriate defense gene expression. Upon defense activation, HOS15 preferentially associates with phosphorylated NPR1 to stimulate rapid degradation of transcriptionally active NPR1 and thus limit the extent of defense gene expression. Our findings indicate that HOS15-mediated ubiquitination and elimination of NPR1 produce effects contrary to those of CUL3-containing ubiquitin ligase that coactivate defense gene expression. Thus, HOS15 plays a key role in the dynamic regulation of pre- and postactivation host defense.

Prevalence and clinical characteristics of allergic rhinitis in the elderly Korean population.

PURPOSE: The proportion of elderly people aged ≥ 65 years is increasing worldwide. Although the reported prevalence of sinonasal disease can vary according to the diagnostic methods used, differences in allergic rhinitis prevalence in the elderly according to diagnostic method have not been reported. We thus aimed to evaluate allergic rhinitis prevalence in the elderly according to diagnostic criteria obtained from questionnaires, physician diagnoses, and allergy tests. METHODS: We compared the allergic rhinitis prevalence in the elderly aged ≥ 65 years with adults aged 19-64 years, using data from the Korean National Health and Nutrition Examination Survey 2008-2012. Total serum IgE and IgE levels specific to allergens of Dermatophagoides farina, cockroach, and dog dander were examined, and factors affecting specific IgE levels were investigated. RESULTS: Allergic rhinitis prevalence according to the questionnaire responses, physician diagnoses, and allergy test results was 35.02%, 14.89%, and 17.56%, respectively. The prevalence based on all diagnostic methods assessed was significantly lower in the elderly than in the general adult group (p < 0.001). Rhinorrhea incidence was significantly increased in the elderly (p = 0.018). Sensitization to Dermatophagoides farina was significantly decreased in the elderly (p = 0.006) and did not correlate with socioeconomic status and/or general health factors. CONCLUSIONS: The elderly population has a distinct clinical presentation, including a low prevalence of allergic rhinitis, and an increased incidence of rhinorrhea symptoms, compared with the general adult population. The management of allergic rhinitis in elderly patients may therefore require a different therapeutic approach to improve rhinorrhea rather than nasal obstruction.

Trans-tympanic Cartilage Chip Insertion for Intractable Patulous Eustachian Tube.

BACKGROUND AND OBJECTIVES: Patulous Eustachian tube (PET) causes troublesome autophony. We treated PET using tragal cartilage chip insertion to fill in the concavity within the tubal valve and evaluated the feasibility of this method. SUBJECTS AND METHODS: This study used a prospective design. Eleven patients with PET disorder were included. Tragal cartilage chip insertion via a transcanal approach into the Eustachian tube (ET) was performed in 14 ears of those patients. They were followed-up for at least 12 months after surgery and were evaluated by symptom questionnaire scores. RESULTS: The average follow-up was 16.4 months. Thirteen of fourteen ears received immediate complete relief of autophony symptoms. Autophony symptoms at the last follow-up were as follows: four ears (28.6%) had complete relief; five ears (35.7%) showed satisfactory improvement; four ears (28.6%) showed significant but unsatisfactory improvement; and one ear (7.1%) was unchanged. The PET symptom questionnaire in the affected ears showed a significant reduction in autophony (p=0.047) and improvement in breathing sound conduction (p=0.047). There were no complications such as otitis media or occlusion symptom. CONCLUSIONS: Transtympanic cartilage chip insertion into the ET provides a safe and accessible surgical option for the treatment of PET.

Enzymatic and metabolic engineering for efficient production of syringin, sinapyl alcohol 4-O-glucoside, in Arabidopsis thaliana.

To promote efficient production of syringin, a plant-derived bioactive monolignol glucoside, synergistic effects of enzymatic and metabolic engineering were combined. Recombinant UGT72E3/E2 chimeras, generated by exchanging parts of the C-terminal domain including the Putative Secondary Plant Glycosyltransferase (PSPG) motif of UGT72E3 and UGT72E2, were expressed in leaves of transgenic Arabidopsis plants; syringin production was measured in vivo and by enzymatic assays in vitro. In both tests, UGT72E3/2 displayed substrate specificity for sinapyl alcohol like the parental enzyme UGT72E3, and the syringin production was significantly increased compared to UGT72E3. In particular, in the in vitro assay, which was performed in the presence of a high concentration of sinapyl alcohol, the production of syringin by UGT72E3/2 was 4-fold higher than by UGT72E3. Furthermore, to enhance metabolic flow through the phenylpropanoid pathway and maintain a high basal concentration of sinapyl alcohol in the leaves, UGT72E3/2 was combined with the sinapyl alcohol synthesis pathway gene F5H encoding ferulate 5-hydroxylase and the lignin biosynthesis transcriptional activator MYB58. The resulting UGT72E3/2+F5H+MYB58 OE plants, which simultaneously overexpress these three genes, accumulated a 56-fold higher level of syringin in their leaves than wild-type plants.

Risk factors associated with pterygium and its subtypes in Korea: the Korean National Health and Nutrition Examination Survey 2008-2010.

PURPOSE: To assess the sociodemographic and health-related risk factors associated with pterygium and its subtypes in Korea. METHODS: From 2008 to 2010, a total of 14,920 randomly selected national representative participants of the Korean National Health and Nutrition Examination Survey underwent additional ophthalmologic examinations by the Korean Ophthalmologic Society. The risk factors for pterygium in general or according to subtype (atrophic, intermediate, and fleshy) were identified using multivariate logistic regression analysis. RESULTS: The prevalence of pterygium was 6.7% (95% confidence interval, 5.9-7.5) in subjects aged 30 years or older. Older age, male sex, lower educational level, rural habitation, nonsmoking, and sun exposure were independent risk factors for pterygium. Among subjects with pterygium, older age, male sex, lower educational level, and nonsmoking were independent risk factors for all types of pterygium. Sun exposure for >5 h/d was the independent risk factor for the severe pterygium subtype. CONCLUSIONS: Socioeconomic disparities in pterygium development exist. Proper ocular examination and education to avoid excessive sun exposure would be helpful in reducing disease risk.

Kip-related protein 3 is required for control of endoreduplication in the shoot apical meristem and leaves of Arabidopsis.

The cell cycle plays an important role in the development and adaptation of multicellular organisms; specifically, it allows them to optimally adjust their architecture in response to environmental changes. Kip-related proteins (KRPs) are important negative regulators of cyclin-dependent kinases (CDKs), which positively control the cell cycle during plant development. The Arabidopsis genome possesses seven KRP genes with low sequence similarity and distinct expression patterns; however, why Arabidopsis needs seven KRP genes and how these genes function in cell cycle regulation are unknown. Here, we focused on the characterization of KRP3, which was found to have unique functions in the shoot apical meristem (SAM) and leaves. KRP3 protein was localized to the SAM, including the ground meristem and vascular tissues in the ground part of the SAM and cotyledons. In addition, KRP3 protein was stabilized when treated with MG132, an inhibitor of the 26S proteasome, indicating that the protein may be regulated by 26S proteasome-mediated protein degradation. KRP3-overexpressing (KRP3 OE) transgenic plants showed reduced organ size, serrated leaves, and reduced fertility. Interestingly, the KRP3 OE transgenic plants showed a significant reduction in the size of the SAM with alterations in cell arrangement. In addition, compared to the wild type, the KRP3 OE transgenic plants had a higher DNA ploidy level in the SAM and leaves. Taken together, our data suggest that KRP3 plays important regulatory roles in the cell cycle and endoreduplication in the SAM and leaves.

Fine mapping and identification of candidate rice genes associated with qSTV11(SG), a major QTL for rice stripe disease resistance.

Rice stripe disease, caused by rice stripe virus (RSV) is a serious constraint to rice production in subtropical regions of East Asia. We performed fine mapping of a RSV resistance QTL on chromosome 11, qSTV11 ( SG ), using near-isogenic lines (NILs, BC(6)F(4)) derived from a cross between the highly resistant variety, Shingwang, and the highly susceptible variety, Ilpum, using 11 insertion and deletion (InDel) markers. qSTV11 ( SG ) was localized to a 150-kb region between InDel 11 (17.86 Mbp) and InDel 5 (18.01 Mbp). Among the two markers in this region, InDel 7 is diagnostic of RSV resistance in 55 Korean japonica and indica rice varieties. InDel 7 could also distinguish the allele type of Nagdong, Shingwang, Mudgo, and Pe-bi-hun from Zenith harboring the Stv-b ( i ) allele. As a result, qSTV11 ( SG ) is likely to be the Stv-b ( i ) allele. There were 21 genes in the 150-kb region harboring the qSTV11 ( SG ) locus. Three of these genes, LOC_Os11g31430, LOC_Os11g31450, and LOC_Os11g31470, were exclusively expressed in the susceptible variety. These expression profiles were consistent with the quantitative nature along with incomplete dominance of RSV resistance. Sequencing of these genes showed that there were several amino acid substitutions between susceptible and resistant varieties. Putative functions of these candidate genes for qSTV11 (SG) are discussed.

Molecular characterization of OsPAP2: transgenic expression of a purple acid phosphatase up-regulated in phosphate-deprived rice suspension cells.

A phosphate starvation-induced, purple, acid phosphatase cDNA was cloned from rice, Oryza sativa. The cDNA encoding the phosphatase (OsPAP2) has 1,893 bp with an open reading frame of 630 amino acid residues. The deduced amino acid sequence of OsPAP2 shows identities of 60-63% with other plant purple acid phosphatases and appears to have five conserved motifs containing the residues involved in metal binding. OsPAP2 expression is up-regulated in the rice plant and in cell cultures in the absence of phosphate (P( i )). The induced expression of OsPAP2 is a specific response to P( i ) starvation, and is not affected by the deprivation of other nutrients. OsPAP2 expression was responsive to the level of P( i )-supply, and transcripts of OsPAP2 were abundant in P( i )-deprived roots. The OsPAP2 cDNA was expressed as a 69 kDa polypeptide in baculovirus-infected insect Sf9 cells. In addition, the OsPAP2 gene was introduced into Arabidopsis via an Agrobacterium-mediated transformation. Functional expression of the OsPAP2 gene in the transgenic Arabidopsis line was confirmed by northern and western blot analyses, as well as by phosphatase activity assays. These results suggest that the OsPAP2 gene can be used to develop new transgenic dicotyledonous plants that are able to adapt to P( i )-deficient conditions.

Increased expression of OsPT1, a high-affinity phosphate transporter, enhances phosphate acquisition in rice.

Most high-affinity phosphate transporter genes (OsPTs) in rice were highly induced in roots when phosphate was depleted. OsPT1, however, was highly expressed in primary roots and leaves regardless of external phosphate concentrations. This finding was confirmed histochemically using transgenic rice plants that express the GUS reporter gene under the control of the OsPT1 promoter, which exhibited high GUS activity even in the phosphate sufficient condition. Furthermore, transgenic rice plants overexpressing the OsPT1 gene accumulated almost twice as much phosphate in the shoots as did wild-type plants. As a result, transgenic plants had more tillers than did wild-type plants, which is a typical physiological indicator for phosphate status in rice.

Suppression of reactive oxygen species by glyceraldehyde-3-phosphate dehydrogenase.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), a classical glycolytic enzyme, is involved in cellular energy production and has important housekeeping functions. In this report, we show that a GAPDH from Arabidopsis, GAPDHa, has a novel function involved in H(2)O(2)-mediated cell death in yeast and Arabidopsis protoplasts. GAPDHa was cloned along with other plant genes that suppress Bax-induced cell death in yeast. Flow cytometry analyses with dihydrorhodamine 123 indicated that H(2)O(2) production mediated by Bax expression in yeast cells was greatly reduced when Bax was coexpressed with GAPDHa. In plants, GAPDHa transcript levels were greatly increased by H(2)O(2) treatment. Furthermore, transformation of GAPDHa into Arabidopsis protoplasts strongly suppressed heat shock-induced H(2)O(2) production and cell death. Together, our results indicate that GAPDH controls generation of H(2)O(2) by Bax and heat shock, which in turn suppresses cell death in yeast and plant cells.

A phosphate starvation-induced acid phosphatase from Oryza sativa: phosphate regulation and transgenic expression.

A phosphate starvation-induced acid phosphatase cDNA was cloned from the rice, Oryza sativa. The cDNA encoding O. sativa acid phosphatase (OsACP1) has 1100 bp with an open reading frame of 274 amino acid residues. The deduced amino acid sequence of OsACP1 cDNA showed 53% identity to tomato acid phosphatase and 46-50% identity to several other plant phosphatases. OsACP1 expression was up-regulated in the rice plant and in cell culture in the absence of phosphate (Pi). The induced expression of OsACP1 was a specific response to Pi starvation, and was not affected by the deprivation of other nutrients. OsACP1 expression was responsive to the level of Pi supply, with transcripts of OsACP1 being abundant in Pi-deprived root. The OsACP1 cDNA was expressed as a 30 kDa polypeptide in baculovirus-infected insect Sf9 cells. In addition, the OsACP1 gene was introduced into Arabidopsis via Agrobacterium-mediated transformation. Functional expression of the OsACP1 gene in the transgenic Arabidopsis lines was confirmed by Northern blot and Western blot analyses, as well as phosphatase activity assays. These results suggest that the OsACP1 gene can be used to develop new transgenic dicotyledonous plants able to adapt to Pi-deficient conditions.

Salicylic acid-mediated innate immunity in Arabidopsis is regulated by SIZ1 SUMO E3 ligase.

Reversible modifications of target proteins by small ubiquitin-like modifier (SUMO) proteins are involved in many cellular processes in yeast and animals. Yet little is known about the function of sumoylation in plants. Here, we show that the SIZ1 gene, which encodes an Arabidopsis SUMO E3 ligase, regulates innate immunity. Mutant siz1 plants exhibit constitutive systemic-acquired resistance (SAR) characterized by elevated accumulation of salicylic acid (SA), increased expression of pathogenesis-related (PR) genes, and increased resistance to the bacterial pathogen Pseudomonas syringae pv. tomato (Pst) DC3000. Transfer of the NahG gene to siz1 plants results in reversal of these phenotypes back to wild-type. Analyses of the double mutants, npr1 siz1, pad4 siz1 and ndr1 siz1 revealed that SIZ1 controls SA signalling. SIZ1 interacts epistatically with PAD4 to regulate PR expression and disease resistance. Consistent with these observations, siz1 plants exhibited enhanced resistance to Pst DC3000 expressing avrRps4, a bacterial avirulence determinant that responds to the EDS1/PAD4-dependent TIR-NBS-type R gene. In contrast, siz1 plants were not resistant to Pst DC3000 expressing avrRpm1, a bacterial avirulence determinant that responds to the NDR1-dependent CC-NBS-type R gene. Jasmonic acid (JA)-induced PDF1.2 expression and susceptibility to Botrytis cinerea were unaltered in siz1 plants. Taken together, these results demonstrate that SIZ1 is required for SA and PAD4-mediated R gene signalling, which in turn confers innate immunity in Arabidopsis.

A duplicated pair of Arabidopsis RING-finger E3 ligases contribute to the RPM1- and RPS2-mediated hypersensitive response.

The Arabidopsis RPM1 protein confers resistance to disease caused by Pseudomonas syringae strains delivering either the AvrRpm1 or AvrB type III effector proteins into host cells. We characterized two closely related RPM1-interacting proteins, RIN2 and RIN3. RIN2 and RIN3 encode RING-finger type ubiquitin ligases with six apparent transmembrane domains and an ubiquitin-binding CUE domain. RIN2 and RIN3 are orthologs of the mammalian autocrine motility factor receptor, a cytokine receptor localized in both plasma membrane caveolae and the endoplasmic reticulum. RIN2 is predominantly localized to the plasma membrane, as are RPM1 and RPS2. The C-terminal regions of RIN2 and RIN3, including the CUE domain, interact strongly with an RPM1 N-terminal fragment and weakly with a similar domain from the Arabidopsis RPS2 protein. RIN2 and RIN3 can dimerize through their C-terminal regions. The RING-finger domains of RIN2 and RIN3 encode ubiquitin ligases. Inoculation with P. syringae DC3000(avrRpm1) or P. syringae DC3000(avrRpt2) induces differential decreases of RIN2 mobility in SDS-PAGE and disappearance of the majority of RIN2. A rin2 rin3 double mutant expresses diminished RPM1- and RPS2-dependent hypersensitive response (HR), but no alteration of pathogen growth. Thus, the RIN2/RIN3 RING E3 ligases apparently act on a substrate that regulates RPM1- and RPS2-dependent HR.