Molecular Biology of the Cell最新文献_第3页

Big1 is a newly identified autophagy regulator that is critical for a fully functional V-ATPase. Big1 是一种新发现的自噬调节因子，对于 V-ATP 酶的全面发挥作用至关重要。

IF 3.3 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-11 DOI: 10.1091/mbc.e24-04-0189

Yuchen Lei,Ying Yang,Zhihai Zhang,Ruoxi Zhang,Xinxin Song,Sami N Malek,Daolin Tang,Daniel J Klionsky

引用次数: 0

Measurement of solubility product reveals the interplay of oligomerization and self-association for defining condensate formation. 溶度积的测量揭示了低聚物和自结合在确定凝结物形成方面的相互作用。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-24 DOI: 10.1091/mbc.E24-01-0030

Aniruddha Chattaraj, Zeynep Baltaci, Steve Chung, Bruce J Mayer, Leslie M Loew, Jonathon A Ditlev

{"title":"Measurement of solubility product reveals the interplay of oligomerization and self-association for defining condensate formation.","authors":"Aniruddha Chattaraj, Zeynep Baltaci, Steve Chung, Bruce J Mayer, Leslie M Loew, Jonathon A Ditlev","doi":"10.1091/mbc.E24-01-0030","DOIUrl":"10.1091/mbc.E24-01-0030","url":null,"abstract":"Cellular condensates often consist of 10s to 100s of distinct interacting molecular species. Because of the complexity of these interactions, predicting the point at which they will undergo phase separation is daunting. Using experiments and computation, we therefore studied a simple model system consisting of polySH3 and polyPRM designed for pentavalent heterotypic binding. We tested whether the peak solubility product, or the product of the dilute phase concentration of each component, is a predictive parameter for the onset of phase separation. Titrating up equal total concentrations of each component showed that the maximum solubility product does approximately coincide with the threshold for phase separation in both experiments and models. However, we found that measurements of dilute phase concentration include small oligomers and monomers; therefore, a quantitative comparison of the experiments and models required inclusion of small oligomers in the model analysis. Even with the inclusion of small polyPRM and polySH3 oligomers, models did not predict experimental results. This led us to perform dynamic light scattering experiments, which revealed homotypic binding of polyPRM. Addition of this interaction to our model recapitulated the experimentally observed asymmetry. Thus, comparing experiments with simulation reveals that the solubility product can be predictive of the interactions underlying phase separation, even if small oligomers and low affinity homotypic interactions complicate the analysis.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141752085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Cytoplasmic preassembly of the flagellar outer dynein arm complex in Trypanosoma brucei. 布氏锥虫鞭毛外动力臂复合体的细胞质预组装。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-18 DOI: 10.1091/mbc.E24-06-0263

Karthika Balasubramaniam, Tingting He, Helen Chen, Zhewang Lin, Cynthia Y He

{"title":"Cytoplasmic preassembly of the flagellar outer dynein arm complex in Trypanosoma brucei.","authors":"Karthika Balasubramaniam, Tingting He, Helen Chen, Zhewang Lin, Cynthia Y He","doi":"10.1091/mbc.E24-06-0263","DOIUrl":"10.1091/mbc.E24-06-0263","url":null,"abstract":"The outer dynein arm (ODA) is a large, multimeric protein complex essential for ciliary motility. The composition and assembly of ODA are best characterized in the green algae Chlamydomonas reinhardtii, where individual ODA subunits are synthesized and preassembled into a mature complex in the cytosol prior to ciliary import. The single-cellular parasite Trypanosoma brucei contains a motile flagellum essential for cell locomotion and pathogenesis. Similar to human motile cilia, T. brucei flagellum contains a two-headed ODA complex arranged at 24 nm intervals along the axonemal microtubule doublets. The subunit composition and the preassembly of the ODA complex in T. brucei, however, have not been investigated. In this study, we affinity-purified the ODA complex from T. brucei cytoplasmic extract. Proteomic analyses revealed the presence of two heavy chains (ODAα and ODAβ), two intermediate chains (IC1and IC2) and several light chains. We showed that both heavy chains and both intermediate chains are indispensable for flagellar ODA assembly. Our study also provided biochemical evidence supporting the presence of a cytoplasmic, preassembly pathway for T. brucei ODA.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141723948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dysregulation of ceramide metabolism causes phytoceramide-dependent induction of the unfolded protein response. 神经酰胺代谢失调导致植物神经酰胺依赖性地诱导折叠蛋白反应

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-18 DOI: 10.1091/mbc.E24-03-0121

Tamayanthi Rajakumar, Md Amin Hossain, Sylwia A Stopka, Yagmur Micoogullari, Jessie Ang, Nathalie Y R Agar, John Hanna

{"title":"Dysregulation of ceramide metabolism causes phytoceramide-dependent induction of the unfolded protein response.","authors":"Tamayanthi Rajakumar, Md Amin Hossain, Sylwia A Stopka, Yagmur Micoogullari, Jessie Ang, Nathalie Y R Agar, John Hanna","doi":"10.1091/mbc.E24-03-0121","DOIUrl":"10.1091/mbc.E24-03-0121","url":null,"abstract":"The unfolded protein response (UPR) detects and mitigates the harmful effects of dysregulated endoplasmic reticulum (ER) function. The UPR has been best characterized as a protein quality control response, and the sole UPR sensor in yeast, Ire1, is known to detect misfolded ER proteins. However, recent work suggests the UPR can also sense diverse defects within the ER membrane, including increased fatty acid saturation and altered phospholipid abundance. These and other lipid-related stimuli have been referred to as lipid bilayer stress and may be sensed independently through Ire1's transmembrane domain. Here, we show that the loss of Isc1, a phospholipase that catabolizes complex ceramides, causes UPR induction, even in the absence of exogenous stress. A series of chemical and genetic approaches identified a requirement for very long-chain fatty acid (VLCFA)-containing phytoceramides for UPR induction. In parallel, comprehensive lipidomics analyses identified large increases in the abundance of specific VLCFA-containing phytoceramides in the isc1Δ mutant. We failed to identify evidence of an accompanying defect in protein quality control or ER-associated protein degradation. These results extend our understanding of lipid bilayer stress in the UPR and provide a foundation for mechanistic investigation of this fascinating intersection between ceramide metabolism, membrane homeostasis, and the UPR.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141723949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ninein domains required for its localization, association with partners dynein and ensconsin, and microtubule organization. Ninein 的定位、与伙伴 dynein 和 ensconsin 的结合以及微管组织所需的结构域。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-18 DOI: 10.1091/mbc.E23-06-0245

Marisa M L Tillery, Chunfeng Zheng, Yiming Zheng, Timothy L Megraw

引用次数: 0

The LCLAT1/LYCAT acyltransferase is required for EGF-mediated phosphatidylinositol-3,4,5-trisphosphate generation and Akt signaling. LCLAT1/LYCAT酰基转移酶是 EGF 介导的磷脂酰肌醇-3,4,5-三磷酸酯生成和 Akt 信号传导所必需的。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-18 DOI: 10.1091/mbc.E23-09-0361

Victoria Chan, Cristina Camardi, Kai Zhang, Laura A Orofiamma, Karen E Anderson, Jafarul Hoque, Leslie N Bone, Yasmin Awadeh, Daniel K C Lee, Norman J Fu, Jonathan T S Chow, Leonardo Salmena, Len R Stephens, Phillip T Hawkins, Costin N Antonescu, Roberto J Botelho

{"title":"The LCLAT1/LYCAT acyltransferase is required for EGF-mediated phosphatidylinositol-3,4,5-trisphosphate generation and Akt signaling.","authors":"Victoria Chan, Cristina Camardi, Kai Zhang, Laura A Orofiamma, Karen E Anderson, Jafarul Hoque, Leslie N Bone, Yasmin Awadeh, Daniel K C Lee, Norman J Fu, Jonathan T S Chow, Leonardo Salmena, Len R Stephens, Phillip T Hawkins, Costin N Antonescu, Roberto J Botelho","doi":"10.1091/mbc.E23-09-0361","DOIUrl":"10.1091/mbc.E23-09-0361","url":null,"abstract":"Receptor tyrosine kinases such as EGF receptor (EGFR) stimulate phosphoinositide 3 kinases to convert phosphatidylinositol-4,5-bisphosophate [PtdIns(4,5)P2] into phosphatidylinositol-3,4,5-trisphosphate [PtdIns(3,4,5)P3]. PtdIns(3,4,5)P3 then remodels actin and gene expression, and boosts cell survival and proliferation. PtdIns(3,4,5)P3 partly achieves these functions by triggering activation of the kinase Akt, which phosphorylates targets like Tsc2 and GSK3β. Consequently, unchecked upregulation of PtdIns(3,4,5)P3-Akt signaling promotes tumor progression. Interestingly, 50-70% of PtdIns and PtdInsPs have stearate and arachidonate at sn-1 and sn-2 positions of glycerol, respectively, forming a species known as 38:4-PtdIns/PtdInsPs. LCLAT1 and MBOAT7 acyltransferases partly enrich PtdIns in this acyl format. We previously showed that disruption of LCLAT1 lowered PtdIns(4,5)P2 levels and perturbed endocytosis and endocytic trafficking. However, the role of LCLAT1 in receptor tyrosine kinase and PtdIns(3,4,5)P3 signaling was not explored. Here, we show that LCLAT1 silencing in MDA-MB-231 and ARPE-19 cells abated the levels of PtdIns(3,4,5)P3 in response to EGF signaling. Importantly, LCLAT1-silenced cells were also impaired for EGF-driven and insulin-driven Akt activation and downstream signaling. Thus, our work provides first evidence that the LCLAT1 acyltransferase is required for receptor tyrosine kinase signaling.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141723952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

γ-tubulin complex controls the nucleation of tubulin-based structures in Apicomplexa. γ-微管蛋白复合物控制着微管蛋白结构的成核。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-24 DOI: 10.1091/mbc.E24-03-0100

Romuald Haase, Annet Puthenpurackal, Bohumil Maco, Amandine Guérin, Dominique Soldati-Favre

{"title":"γ-tubulin complex controls the nucleation of tubulin-based structures in Apicomplexa.","authors":"Romuald Haase, Annet Puthenpurackal, Bohumil Maco, Amandine Guérin, Dominique Soldati-Favre","doi":"10.1091/mbc.E24-03-0100","DOIUrl":"10.1091/mbc.E24-03-0100","url":null,"abstract":"Apicomplexan parasites rely on tubulin structures throughout their cell and life cycles, particularly in the polymerization of spindle microtubules to separate the replicated nucleus into daughter cells. Additionally, tubulin structures, including conoid and subpellicular microtubules, provide the necessary rigidity and structure for dissemination and host cell invasion. However, it is unclear whether these tubulin structures are nucleated via a highly conserved γ-tubulin complex or through a specific process unique to apicomplexans. This study demonstrates that Toxoplasma γ-tubulin is responsible for nucleating spindle microtubules, akin to higher eukaryotes, facilitating nucleus division in newly formed parasites. Interestingly, γ-tubulin colocalizes with nascent conoid and subpellicular microtubules during division, potentially nucleating these structures as well. Loss of γ-tubulin results in significant morphological defects due to impaired nucleus scission and the loss of conoid and subpellicular microtubule nucleation, crucial for parasite shape and rigidity. Additionally, the nucleation process of tubulin structures involves a concerted action of γ-tubulin and Gamma Tubulin Complex proteins (GCPs), recapitulating the localization and phenotype of γ-tubulin. This study also introduces new molecular markers for cytoskeletal structures and applies iterative expansion microscopy to reveal microtubule-based architecture in Cryptosporidium parvum sporozoites, further demonstrating the conserved localization and probable function of γ-tubulin in Cryptosporidium.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141752087","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Characterization of hyperactive mutations in the renal potassium channel ROMK uncovers unique effects on channel biogenesis and ion conductance. 肾脏钾离子通道 ROMK 的超活性突变特征揭示了其对通道生物生成和离子传导的独特影响。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-18 DOI: 10.1091/mbc.E23-12-0494

Nga H Nguyen, Shaohu Sheng, Anupam Banerjee, Christopher J Guerriero, Jingxin Chen, Xueqi Wang, Timothy D Mackie, Paul A Welling, Thomas R Kleyman, Ivet Bahar, Anne E Carlson, Jeffrey L Brodsky

{"title":"Characterization of hyperactive mutations in the renal potassium channel ROMK uncovers unique effects on channel biogenesis and ion conductance.","authors":"Nga H Nguyen, Shaohu Sheng, Anupam Banerjee, Christopher J Guerriero, Jingxin Chen, Xueqi Wang, Timothy D Mackie, Paul A Welling, Thomas R Kleyman, Ivet Bahar, Anne E Carlson, Jeffrey L Brodsky","doi":"10.1091/mbc.E23-12-0494","DOIUrl":"10.1091/mbc.E23-12-0494","url":null,"abstract":"Hypertension affects one billion people worldwide and is the most common risk factor for cardiovascular disease, yet a comprehensive picture of its underlying genetic factors is incomplete. Amongst regulators of blood pressure is the renal outer medullary potassium (ROMK) channel. While select ROMK mutants are prone to premature degradation and lead to disease, heterozygous carriers of some of these same alleles are protected from hypertension. Therefore, we hypothesized that gain-of-function (GoF) ROMK variants which increase potassium flux may predispose people to hypertension. To begin to test this hypothesis, we employed genetic screens and a candidate-based approach to identify six GoF variants in yeast. Subsequent functional assays in higher cells revealed two variant classes. The first group exhibited greater stability in the endoplasmic reticulum, enhanced channel assembly, and/or increased protein at the cell surface. The second group of variants resided in the PIP2-binding pocket, and computational modeling coupled with patch-clamp studies demonstrated lower free energy for channel opening and slowed current rundown, consistent with an acquired PIP2-activated state. Together, these findings advance our understanding of ROMK structure-function, suggest the existence of hyperactive ROMK alleles in humans, and establish a system to facilitate the development of ROMK-targeted antihypertensives.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141723947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Mechanical strategies supporting growth and size diversity in Filamentous Fungi. 支持丝状真菌生长和大小多样性的机械策略

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-24 DOI: 10.1091/mbc.E24-04-0171

Louis Chevalier, Flora Klingelschmitt, Ludovic Mousseron, Nicolas Minc

{"title":"Mechanical strategies supporting growth and size diversity in Filamentous Fungi.","authors":"Louis Chevalier, Flora Klingelschmitt, Ludovic Mousseron, Nicolas Minc","doi":"10.1091/mbc.E24-04-0171","DOIUrl":"10.1091/mbc.E24-04-0171","url":null,"abstract":"The stereotypical tip growth of filamentous fungi supports their lifestyles and functions. It relies on the polarized remodeling and expansion of a protective elastic cell wall (CW) driven by large cytoplasmic turgor pressure. Remarkably, hyphal filament diameters and cell elongation rates can vary extensively among different fungi. To date, however, how fungal cell mechanics may be adapted to support these morphological diversities while ensuring surface integrity remains unknown. Here, we combined super-resolution imaging and deflation assays to measure local CW thickness, elasticity and turgor in a set of fungal species spread on the evolutionary tree that spans a large range in cell size and growth speeds. While CW elasticity exhibited dispersed values, presumably reflecting differences in CW composition, both thickness and turgor scaled in dose-dependence with cell diameter and growth speeds. Notably, larger cells exhibited thinner lateral CWs, and faster cells thinner apical CWs. Counterintuitively, turgor pressure was also inversely scaled with cell diameter and tip growth speed, challenging the idea that turgor is the primary factor dictating tip elongation rates. We propose that fast-growing cells with rapid CW turnover have evolved strategies based on a less turgid cytoplasm and thin walls to safeguard surface integrity and survival.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141752086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

KLP-7/Kinesin-13 orchestrates axon-dendrite checkpoints for polarized trafficking in neurons. KLP-7/Kinesin-13为神经元的极化迁移协调轴突-树突检查点。

IF 3.1 3区生物学

Molecular Biology of the Cell Pub Date : 2024-09-01 Epub Date: 2024-07-10 DOI: 10.1091/mbc.E23-08-0335

Swagata Dey, Nitish Kumar, Supraja Balakrishnan, Sandhya P Koushika, Anindya Ghosh-Roy

{"title":"KLP-7/Kinesin-13 orchestrates axon-dendrite checkpoints for polarized trafficking in neurons.","authors":"Swagata Dey, Nitish Kumar, Supraja Balakrishnan, Sandhya P Koushika, Anindya Ghosh-Roy","doi":"10.1091/mbc.E23-08-0335","DOIUrl":"10.1091/mbc.E23-08-0335","url":null,"abstract":"The polarized nature of neurons depends on their microtubule dynamics and orientation determined by both microtubule-stabilizing and destabilizing factors. The role of destabilizing factors in developing and maintaining neuronal polarity is unclear. We investigated the function of KLP-7, a microtubule depolymerizing motor of the Kinesin-13 family, in axon-dendrite compartmentalization using PVD neurons in Caenorhabditis elegans. Loss of KLP-7 caused a mislocalization of axonal proteins, including RAB-3, SAD-1, and their motor UNC-104, to dendrites. This is rescued by cell-autonomous expression of the KLP-7 or colchicine treatment, indicating the involvement of KLP-7-dependent microtubule depolymerization. The high mobility of KLP-7 is correlated to increased microtubule dynamics in the dendrites, which restricts the enrichment of UNC-44, an integral component of Axon Initial Segment (AIS) in these processes. Due to the loss of KLP-7, ectopic enrichment of UNC-44 in the dendrite potentially redirects axonal traffic into dendrites that include plus-end out microtubules, axonal motors, and cargoes. These observations indicate that KLP-7-mediated depolymerization defines the microtubule dynamics conducive to the specific enrichment of AIS components in dendrites. This further compartmentalizes dendritic and axonal microtubules, motors, and cargoes, thereby influencing neuronal polarity.","PeriodicalId":18735,"journal":{"name":"Molecular Biology of the Cell","volume":null,"pages":null},"PeriodicalIF":3.1,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7616348/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141580241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0