The BCL-2 family protein BCL-RAMBO interacts and cooperates with GRP75 to promote its apoptosis signaling pathway.

The BCL-2 family protein BCL-RAMBO, also known as BCL2-like 13, anchors at the outer mitochondrial membrane and regulates apoptosis, mitochondrial fragmentation, and mitophagy. However, the mechanisms underlying the proapoptotic role of BCL-RAMBO remain unclear. In the present study, we demonstrated that BCL-RAMBO interacted with glucose-regulated protein 75 (GRP75), also known as heat shock protein family A member 9, and mortalin using co-immunoprecipitation and glutathione S-transferase-based pull-down assays. BCL-RAMBO interacted with GRP75 via its No BCL-2 homology domain. The interaction between BCL-RAMBO and GRP75 was confirmed by genetic interactions in Drosophila because a rough eye phenotype caused by the ectopic expression of BCL-RAMBO was partially suppressed by mutations in Hsc70-5, a mammalian GRP75 ortholog. In human embryonic kidney 293T cells, the co-expression of BCL-RAMBO and GRP75 facilitated an elevation in executioner caspase activity and poly (ADP-ribose) polymerase 1 (PARP-1) cleavage. In contrast, the knockdown of GRP75 suppressed elevated executioner caspase activity and PARP-1 cleavage in BCL-RAMBO-transfected cells. The mitochondrial release of cytochrome c induced by BCL-RAMBO was also attenuated by the knockdown of GRP75. These results indicate that GRP75 interacts with BCL-RAMBO and plays a crucial role in the BCL-RAMBO-dependent apoptosis signaling pathway.

PGAM5 interacts with Bcl-rambo and regulates apoptosis and mitophagy.

Bcl-rambo, also known as BCL2L13, has been reported to regulate apoptosis, mitochondrial fragmentation, and mitophagy. However, the molecular mechanisms by which Bcl-rambo regulates these processes currently remain unclear. In the present study, we identified phosphoglycerate mutase member 5 (PGAM5) as an emerging partner interacting with Bcl-rambo through phenotypic Drosophila screening. The rough eye phenotype induced by human Bcl-rambo was partly rescued by the knockdown of pgam5-2, a mammalian ortholog of PGAM5. Bcl-rambo bound to PGAM5, and their interaction required the Bcl-rambo transmembrane domain. The co-expression of Bcl-rambo and PGAM5 promoted effector caspase activity in human embryonic kidney 293T cells. The transient overexpression of Bcl-rambo increased LC3B-II levels, which had been decreased by the co-expression of PGAM5. These results suggest that PGAM5 promotes Bcl-rambo-dependent apoptosis, but conversely interferes with Bcl-rambo-dependent mitophagy.

Impact of a Rehabilitation Protocol and a Dedicated Therapist in the Intensive Care Unit on Physical Function and Activities of Daily Living.

OBJECTIVES: The goal of this study was to determine the effects of an intensive care unit (ICU) rehabilitation protocol with dedicated therapists on the physical function and activities of daily living (ADL) of patients on discharge from the ICU. METHODS: This retrospective study included patients who started rehabilitation during their ICU stay. Patients were divided into three groups: the Usual Care group (before the introduction of the rehabilitation protocol), the Protocol group (after the introduction of the rehabilitation protocol), and the PT + Protocol group (with a dedicated therapist in addition to the rehabilitation protocol). The standard interventions in the Protocol group and the PT + Protocol group were set according to the protocol based on the level of consciousness and strength of each individual patient. Patients' age, APACHE II score, length of ICU stay, length of hospital stay, and the Functional Status Score for the ICU (FSS-ICU) and Medical Research Council score (MRC score) on discharge from the ICU were compared among the three groups. RESULTS: There were no significant differences among the three groups in age and APACHE II score. The MRC and FSS-ICU scores were significantly higher in the PT + Protocol and Protocol groups than in the Usual Care group. Furthermore, the lengths of ICU stay and hospital stay were lower in the PT + Protocol group than in the Usual Care group. CONCLUSIONS: Introduction of the rehabilitation protocol improved the limb strength and ADL of patients. Moreover, the presence of dedicated therapists in addition to the protocol reduced the lengths of ICU and hospital stays.