In plants, the cortical endoplasmic reticulum (ER) network is connected to the plasma membrane (PM) through the ER-PM contact sites (EPCSs), whose structures are maintained by EPCS resident proteins ...and the cytoskeleton.1–7 Strong co-alignment between EPCSs and the cytoskeleton is observed in plants,1,8 but little is known of how the cytoskeleton is maintained and regulated at the EPCS. Here, we have used a yeast-two-hybrid screen and subsequent in vivo interaction studies in plants by fluorescence resonance energy transfer (FRET)-fluorescence lifetime imaging microscopy (FLIM) analysis to identify two microtubule binding proteins, KLCR1 (kinesin-light-chain-related protein 1) and IQD2 (IQ67-domain 2), that interact with the actin binding protein NET3C and form a component of plant EPCS that mediates the link between the actin and microtubule networks. The NET3C-KLCR1-IQD2 module, acting as an actin-microtubule bridging complex, has a direct influence on ER morphology and EPCS structure. Their loss-of-function mutants, net3a/NET3C RNAi, klcr1, or iqd2, exhibit defects in pavement cell morphology, which we suggest is linked to the disorganization of both actin filaments and microtubules. In conclusion, our results reveal a novel cytoskeletal-associated complex, which is essential for the maintenance and organization of cytoskeletal structure and ER morphology at the EPCS and for normal plant cell morphogenesis.
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•A new plant actin-microtubule bridging complex in plants: NET3C-KLCR1-IQD2•The complex mediates the link between the cytoskeleton and ER at the ER-PM interface•Their loss-of-function mutants exhibit defects in pavement cell morphology•The phenotype is likely caused by disorganization of cytoskeletal and ER structure
Zang et al. identify a novel cytoskeletal complex mediating the link between actin, microtubules, and the ER network at the ER-PM interface. This protein complex controls the organization of the cytoskeletal system and ER morphology, which is essential for normal plant cell morphogenesis.
Oesophagectomy remains the only curative intervention for oesophageal cancer, with defined nutritional and health-related quality of life (HR-QOL) consequences. It follows therefore that there is a ...significant risk of decline in physical wellbeing with oesophagectomy however this has been inadequately quantified. This study prospectively examines change in physical functioning and habitual physical activity participation, from pre-surgery through 6-months post-oesophagectomy.
Patients scheduled for oesophagectomy with curative intent were recruited. Key domains of physical functioning including exercise tolerance (six-minute walk test (6MWT)) and muscle strength (hand-grip strength), and habitual physical activity participation, including sedentary behaviour (accelerometry) were measured pre-surgery (T0) and repeated at 1-month (T1) and 6-months (T2) post-surgery. HR-QOL was measured using the EORTC-QOL C30.
Thirty-six participants were studied (mean age 62.4 (8.8) years, n = 26 male, n = 26 transthoracic oesophagectomy). Mean 6MWT distance decreased significantly from T0 to T1 (p = 0.006) and returned to T0 levels between T1 and T2 (p < 0.001). Percentage time spent sedentary increased throughout recovery (p < 0.001) and remained significantly higher at T2 in comparison to T0 (p = 0.003). In contrast, percentage time spent engaged in either light or moderate-to-vigorous intensity activity, all reduced significantly (p < 0.001 for both) and remained significantly lower at T2 in comparison to T0 (p = 0.009 and p = 0.01 respectively). Patients reported deficits in multiple domains of HR-QOL during recovery including global health status (p = 0.04), physical functioning (p < 0.001) and role functioning (p < 0.001). Role functioning remained a clinically important 33-points lower than pre-operative values at T2.
Habitual physical activity participation remains significantly impaired at 6-months post-oesophagectomy. Physical activity is a measurable and modifiable target for physical rehabilitation, which is closely aligned with patient-reported deficits in role functioning. Rehabilitation aimed at optimising physical health in oesophageal cancer survivorship is warranted.
In plants, exocyst subunit isoforms exhibit significant functional diversity in that they are involved in either protein secretion or autophagy, both of which are essential for plant development and ...survival. Although the molecular basis of autophagy is widely reported, its contribution to plant reproduction is not very clear. Here, we have identified Exo84c, a higher plant-specific Exo84 isoform, as having a unique function in modulating exocytotic compartment degradation during stigmatic tissue senescence. This process is achieved through its interaction with the ER localised VAP27 proteins, which regulate the turnover of Exo84c through the autophagy pathway. VAP27 recruits Exo84c onto the ER membrane as well as numerous ER-derived autophagosomes that are labelled with ATG8. These Exo84c/exocyst and VAP27 positive structures are accumulated in the vacuole for degradation, and this process is partially perturbed in the exo84c knock-out mutants. Interestingly, the exo84c mutant showed a prolonged effective pollination period with higher seed sets, possibly because of the delayed stigmatic senescence when Exo84c regulated autophagy is blocked. In conclusion, our studies reveal a link between the exocyst complex and the ER network in regulating the degradation of exocytosis vesicles, a process that is essential for normal papilla cell senescence and flower receptivity.
The self-incompatibility system evolves in angiosperms to promote cross-pollination by rejecting self-pollination. Here, we show the involvement of Exo84c in the SI response of both Brassica napus ...and Arabidopsis. The expression of Exo84c is specifically elevated in stigma during the SI response. Knocking out Exo84c in B. napus and SI Arabidopsis partially breaks down the SI response. The SI response inhibits both the protein secretion in papillae and the recruitment of the exocyst complex to the pollen-pistil contact sites. Interestingly, these processes can be partially restored in exo84c SI Arabidopsis. After incompatible pollination, the turnover of the exocyst-labeled compartment is enhanced in papillae. However, this process is perturbed in exo84c SI Arabidopsis. Taken together, our results suggest that Exo84c regulates the exocyst complex vacuolar degradation during the SI response. This process is likely independent of the known SI pathway in Brassicaceae to secure the SI response.
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•The expression of Exo84c is upregulated specifically in SI response•Suppression of Exo84c results in the breakdown of SI response•Protein secretion is blocked in SI response•Exo84c mediates the vacuolar degradation of exocytic compartments in SI response
Many plants have used self-incompatibility to avoid inbreeding and promote outcrossing to maintain genetic diversity. Zhang et al. identify that Exo84c is required for SI response by mediating the vacuolar degradation of exocytic compartments in Brassicaceae species.
Purpose
Patients with metastatic cancer can experience debilitating symptoms, which may influence attitudes towards and engagement in physical activity. This study aimed to examine the attitudes of ...patients living with metastatic prostate cancer towards physical activity.
Materials and methods
Semi-structured interviews were completed with male patients living with metastatic prostate cancer. Interviews included eight questions related to patients’ attitudes towards physical activity. Content analysis was conducted on the transcribed interview data. Twenty men with metastatic prostate cancer (mean age 71 ± 8.5 years; body mass index 30.19 ± 5.37 kg/cm
2
) and associated bone metastases (55% with > 2 regions affected) participated in the study.
Results
Men’s views towards physical activity were coded into the following major themes: (1) barriers to physical activity, (2) benefits of physical activity, (3) a reduction in physical activity levels post diagnosis and (4) social support for physical activity. Symptoms of metastatic prostate cancer and treatment side effects including pain and fatigue negatively influenced activity participation. In addition, many generic barriers to physical activity were described such as bad weather and a lack of suitable facilities for exercising in rural areas.
Conclusion
Men living with metastatic prostate cancer have unique needs regarding physical activity related to symptoms of both their cancer and cancer treatment. There is a need to increase prompts that encourage those with metastatic prostate cancer to maintain/increase physical activity levels post diagnosis. Given the individualised needs of this patient group, referral to a cancer exercise specialist should be considered for prescription of tailored physical activity programmes.
Trial registration
Clinicaltrials.gov
NLM Identifier: NCT02453139
Membrane trafficking, organelle movement, and morphogenesis in plant cells are mainly controlled by the actin cytoskeleton. Not all proteins that regulate the cytoskeleton and membrane dynamics in ...animal systems have functional homologs in plants, especially for those proteins that form the bridge between the cytoskeleton and membrane; the membrane-actin adaptors. Their nature and function is only just beginning to be elucidated and this field has been greatly enhanced by the recent identification of the NETWORKED (NET) proteins, which act as membrane-actin adaptors. In this review, we will summarize the role of the actin cytoskeleton and its regulatory proteins in their interaction with endomembrane compartments and where they potentially act as platforms for cell signaling and the coordination of other subcellular events.
Background
The poor prognosis and rising incidence of esophageal adenocarcinoma highlight the need for improved detection methods. The potential for circulating microRNAs (miRNAs) as biomarkers in ...other cancers has been shown, but circulating miRNAs have not been well characterized in esophageal adenocarcinoma. We investigated whether circulating exosomal miRNAs have potential to discriminate individuals with esophageal adenocarcinoma from healthy controls and non-dysplastic Barrett’s esophagus.
Methods
Seven hundred fifty-eight miRNAs were profiled in serum circulating exosomes from a cohort of 19 healthy controls, 10 individuals with Barrett’s esophagus, and 18 individuals with locally advanced esophageal adenocarcinoma. MiRNA expression was assessed using all possible permutations of miRNA ratios per individual. Four hundred eight miRNA ratios were differentially expressed in individuals with cancer compared to controls and Barrett’s esophagus (Mann-Whitney
U
test,
P
< 0.05). The 179/408 ratios discriminated esophageal adenocarcinoma from healthy controls and Barrett’s esophagus (linear regression,
P
< 0.05; area under receiver operating characteristic (ROC) > 0.7,
P
< 0.05). A multi-biomarker panel (RNU6-1/miR-16-5p, miR-25-3p/miR-320a, let-7e-5p/miR-15b-5p, miR-30a-5p/miR-324-5p, miR-17-5p/miR-194-5p) demonstrated enhanced specificity and sensitivity (area under ROC = 0.99, 95 % CI 0.96–1.0) over single miRNA ratios to distinguish esophageal adenocarcinoma from controls and Barrett’s esophagus.
Conclusions
This study highlights the potential for serum exosomal miRNAs as biomarkers for the detection of esophageal adenocarcinoma.
Plant cells grow through increases in volume and cell wall surface area. The mature morphology of a plant cell is a product of the differential rates of expansion between neighboring zones of the ...cell wall during this process. Filamentous actin arrays are associated with plant cell growth, and the activity of actin-binding proteins is proving to be essential for proper cell morphogenesis. Actin-nucleating proteins participate in cell expansion and cell plate formation whereas the recycling of actin monomers is required to maintain actin dynamics and controlled growth. Coordination of actin-binding protein activity and other aspects of cytoskeletal behavior during cell development maintains cohesive cell expansion. Emerging plant signaling networks are proving to be powerful regulators of morphology-shaping cytoskeletal activity, and in this review we highlight current research in actin network regulation.
Abstract
Members of the NETWORKED (NET) family are involved in actin-membrane interactions. Here we show that two members of the NET family, NET4A and NET4B, are essential for normal guard cell actin ...reorganization, which is a process critical for stomatal closure in plant immunity. NET4 proteins interact with F-actin and with members of the Rab7 GTPase RABG3 family through two distinct domains, allowing for simultaneous localization to actin filaments and the tonoplast. NET4 proteins interact with GTP-bound, active RABG3 members, suggesting their function being downstream effectors. We also show that RABG3b is critical for stomatal closure induced by microbial patterns. Taken together, we conclude that the actin cytoskeletal remodelling during stomatal closure involves a molecular link between actin filaments and the tonoplast, which is mediated by the NET4-RABG3b interaction. We propose that stomatal closure to microbial patterns involves the coordinated action of immune-triggered osmotic changes and actin cytoskeletal remodelling likely driving compact vacuolar morphologies.
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