Role of the Small GTPase Rho3 in Golgi/Endosome Trafficking through Functional Interaction with Adaptin in Fission Yeast

BACKGROUND: We had previously identified the mutant allele of apm1(+) that encodes a homolog of the mammalian µ1A subunit of the clathrin-associated adaptor protein-1 (AP-1) complex, and we demonstrated the role of Apm1 in Golgi/endosome trafficking, secretion, and vacuole fusion in fission yeast. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we isolated rho3(+), which encodes a Rho-family small GTPase, an important regulator of exocystosis, as a multicopy-suppressor of the temperature-sensitive growth of the apm1-1 mutant cells. Overexpression of Rho3 suppressed the Cl(-) sensitivity and immunosuppressant sensitivity of the apm1-1 mutant cells. Overexpression of Rho3 also suppressed the fragmentation of vacuoles, and the accumulation of v-SNARE Syb1 in Golgi/endosomes and partially suppressed the defective secretion associated with apm1-deletion cells. Notably, electron microscopic observation of the rho3-deletion cells revealed the accumulation of abnormal Golgi-like structures, vacuole fragmentation, and accumulation of secretory vesicles; these phenotypes were very similar to those of the apm1-deletion cells. Furthermore, the rho3-deletion cells and apm1-deletion cells showed very similar phenotypic characteristics, including the sensitivity to the immunosuppressant FK506, the cell wall-damaging agent micafungin, Cl(-), and valproic acid. Green fluorescent protein (GFP)-Rho3 was localized at Golgi/endosomes as well as the plasma membrane and division site. Finally, Rho3 was shown to form a complex with Apm1 as well as with other subunits of the clathrin-associated AP-1 complex in a GTP- and effector domain-dependent manner. CONCLUSIONS/SIGNIFICANCE: Taken together, our findings reveal a novel role of Rho3 in the regulation of Golgi/endosome trafficking and suggest that clathrin-associated adaptor protein-1 and Rho3 co-ordinate in intracellular transport in fission yeast. To the best of our knowledge, this study provides the first evidence of a direct link between the small GTPase Rho and the clathrin-associated adaptor protein-1 in membrane trafficking

A case of scleritis associated rheumatoid arthritis accompanying an intraocular elevated lesion

Abstract Background Scleritis and/or uveitis sometimes accompanies patients who suffer from rheumatoid arthritis. However, few studies have reported scleritis and/or uveitis accompanying a fundus elevated lesion, such as an intraocular tumor. In this study, we report a case of rheumatoid uveitis associated with an intraocular elevated lesion. Case presentation A 66-year-old female visited another eye clinic and was diagnosed as bilateral anterior uveitis, and was prescribed steroid eye drops for treatment. She had previously been diagnosed as rheumatoid arthritis at the age of 30 years. Due to vitreous opacity that appeared in her right eye, we increased the instillation of steroid eye drops and the amount of oral prednisolone. Although the inflammation had improved, anterior uveitis relapsed, and an intraocular whitish elevated lesion resembling an intraocular tumor at the superior nasal retina appeared. We speculated this lesion to be a granuloma complicated with rheumatoid arthritis. Thus, we increased the amount of prednisolone administration, and the lesion began to shrink and ultimately fully disappeared. Conclusions We strongly believe that our case’s lesion was a subretinal granuloma related with rheumatoid arthritis, as it disappeared by increased corticosteroid treatment. Our findings show that we should consider rheumatoid arthritis in a differential diagnosis of such types of fundus elevated lesions

Bilateral Cytomegalovirus Retinitis in a Patient with Systemic Lupus Erythematosus

Purpose: The purpose of this study was to report the case of a patient who underwent vitrectomy for bilateral rhegmatogenous retinal detachment caused by cytomegalovirus (CMV) retinitis while undergoing steroid and immunosuppressant therapy for systemic lupus erythematosus (SLE). Case Report: We report on a 29-year-old female who was undergoing steroids and immunosuppressants treatment for SLE at Osaka Medical College Hospital, Takatsuki City, Japan. Examination of the patient due to prolonged and worsening diarrhea revealed positive test results for C7-HRP, and she was diagnosed with CMV colitis. She was subsequently admitted to the hospital and started on intravenous ganciclovir for treatment. Approximately 1.5 months later, her primary complaint was deterioration of the upper visual field in her left eye, and she was then referred to the Department of Ophthalmology. Numerous granular exudative spots were found around the lower retinal area of her left eye with retinal breaks that had developed in an area of retinal necrosis that resulted in retinal detachment. After time was allowed for the patient’s general condition to improve, a vitrectomy was performed on that eye. The patient subsequently developed a similar retinal detachment in her right eye, for which she underwent a vitrectomy. Although the patient required multiple surgeries on both eyes, her retinas currently remain reattached and the inflammation has subsided. Conclusion: The findings of this study show that strict attention must be paid to SLE patients on immunosuppressive therapy due to the possible association of CMV retinitis

A Case of Syphilitic Uveitis in Which Vitreous Surgery Was Useful for the Diagnosis and Treatment

Purpose: To report a case of atypical syphilitic uveitis complicated with retinal vasculitis, proliferative retinopathy, and vitreous hemorrhage in which vitreous surgery was useful for the diagnosis and treatment. Case Report: A 38-year-old female was referred to our hospital after noticing visual disturbance in her right eye. Fundoscopy examination of that eye revealed retinal phlebitis accompanied by retinal hemorrhage and soft exudate, and remarkable exudative changes in the retinal vessels from the upper arcade to the macula region. After a blood examination, a serological test showed positive for syphilis; however, systemic findings were scarce. Syphilitic uveitis was suspected, so we administered treatment for syphilis, anticoagulant treatment for retinal vasculitis, steroids for intraocular inflammation, and photocoagulation for the retinal nonperfusion area. However, her visual acuity (VA) decreased to 30 cm/counting fingers due to vitreous hemorrhage resulting from fibrovascular membrane at the optic disc. Since the vitreous hemorrhage was insufficiently absorbed, vitreous surgery was performed to remove the hemorrhage and fibrovascular tissue. Following surgery, the uveitis and retinal vasculitis subsided, and her corrected VA improved to 0.3. Postoperative examination of a fixed quantity of collected vitreous fluid for syphilis showed a Treponema pallidum hemagglutination value of 5,120 times the normal amount, thus confirming the syphilitic uveitis diagnosis. Conclusions: Our findings show that when observing patients with obstructive retinal vasculitis of unknown causes, syphilitic uveitis should be considered as a differential diagnosis, and that vitreous surgery is useful for the diagnosis and treatment of atypical syphilitic uveitis which has progressed to proliferative retinopathy

A Case of Syphilitic Uveitis in Which Vitreous Surgery Was Useful for the Diagnosis and Treatment

Purpose: To report a case of atypical syphilitic uveitis complicated with retinal vasculitis, proliferative retinopathy, and vitreous hemorrhage in which vitreous surgery was useful for the diagnosis and treatment. Case Report: A 38-year-old female was referred to our hospital after noticing visual disturbance in her right eye. Fundoscopy examination of that eye revealed retinal phlebitis accompanied by retinal hemorrhage and soft exudate, and remarkable exudative changes in the retinal vessels from the upper arcade to the macula region. After a blood examination, a serological test showed positive for syphilis; however, systemic findings were scarce. Syphilitic uveitis was suspected, so we administered treatment for syphilis, anticoagulant treatment for retinal vasculitis, steroids for intraocular inflammation, and photocoagulation for the retinal nonperfusion area. However, her visual acuity (VA) decreased to 30 cm/counting fingers due to vitreous hemorrhage resulting from fibrovascular membrane at the optic disc. Since the vitreous hemorrhage was insufficiently absorbed, vitreous surgery was performed to remove the hemorrhage and fibrovascular tissue. Following surgery, the uveitis and retinal vasculitis subsided, and her corrected VA improved to 0.3. Postoperative examination of a fixed quantity of collected vitreous fluid for syphilis showed a Treponema pallidum hemagglutination value of 5,120 times the normal amount, thus confirming the syphilitic uveitis diagnosis. Conclusions: Our findings show that when observing patients with obstructive retinal vasculitis of unknown causes, syphilitic uveitis should be considered as a differential diagnosis, and that vitreous surgery is useful for the diagnosis and treatment of atypical syphilitic uveitis which has progressed to proliferative retinopathy

南部沖縄トラフ多良間海丘に存在する酸化鉄被膜地帯での微生物調査: NT11-18 研究航海概要

http://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt11-18/