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Concha JO, Gutierrez K, Barbosa N, Rodrigues RL, de Carvalho AN, Tavares LA, Rudd JS, Costa CS, Andrade BYG, Espreafico EM, Crump CM, daSilva LLP. Rab27a GTPase and its effector Myosin Va are host factors required for efficient Oropouche virus cell egress. PLoS Pathog 2024; 20:e1012504. [PMID: 39213446 PMCID: PMC11392402 DOI: 10.1371/journal.ppat.1012504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 09/12/2024] [Accepted: 08/14/2024] [Indexed: 09/04/2024] Open
Abstract
Oropouche fever, a debilitating illness common in South America, is caused by Oropouche virus (OROV), an arbovirus. OROV belongs to the Peribunyaviridae family, a large group of RNA viruses. Little is known about the biology of Peribunyaviridae in host cells, especially assembly and egress processes. Our research reveals that the small GTPase Rab27a mediates intracellular transport of OROV induced compartments and viral release from infected cells. We show that Rab27a interacts with OROV glycoproteins and colocalizes with OROV during late phases of the infection cycle. Moreover, Rab27a activity is required for OROV trafficking to the cell periphery and efficient release of infectious particles. Consistently, depleting Rab27a's downstream effector, Myosin Va, or inhibiting actin polymerization also hinders OROV compartments targeting to the cell periphery and infectious viral particle egress. These data indicate that OROV hijacks Rab27a activity for intracellular transport and cell externalization. Understanding these crucial mechanisms of OROV's replication cycle may offer potential targets for therapeutic interventions and aid in controlling the spread of Oropouche fever.
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Affiliation(s)
- Juan O Concha
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Kristel Gutierrez
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Natalia Barbosa
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Roger L Rodrigues
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Andreia N de Carvalho
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Lucas A Tavares
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Jared S Rudd
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Cristina S Costa
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Barbara Y G Andrade
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Enilza M Espreafico
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Colin M Crump
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Luis L P daSilva
- Virus Research Center, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
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Pan J, Zhou R, Yao LL, Zhang J, Zhang N, Cao QJ, Sun S, Li XD. Identification of a third myosin-5a-melanophilin interaction that mediates the association of myosin-5a with melanosomes. eLife 2024; 13:RP93662. [PMID: 38900147 PMCID: PMC11189624 DOI: 10.7554/elife.93662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024] Open
Abstract
Transport and localization of melanosome at the periphery region of melanocyte are depended on myosin-5a (Myo5a), which associates with melanosome by interacting with its adaptor protein melanophilin (Mlph). Mlph contains four functional regions, including Rab27a-binding domain, Myo5a GTD-binding motif (GTBM), Myo5a exon F-binding domain (EFBD), and actin-binding domain (ABD). The association of Myo5a with Mlph is known to be mediated by two specific interactions: the interaction between the exon-F-encoded region of Myo5a and Mlph-EFBD and that between Myo5a-GTD and Mlph-GTBM. Here, we identify a third interaction between Myo5a and Mlph, that is, the interaction between the exon-G-encoded region of Myo5a and Mlph-ABD. The exon-G/ABD interaction is independent from the exon-F/EFBD interaction and is required for the association of Myo5a with melanosome. Moreover, we demonstrate that Mlph-ABD interacts with either the exon-G or actin filament, but cannot interact with both of them simultaneously. Based on above findings, we propose a new model for the Mlph-mediated Myo5a transportation of melanosomes.
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Affiliation(s)
- Jiabin Pan
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Rui Zhou
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Lin-Lin Yao
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Jie Zhang
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Ning Zhang
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Qing-Juan Cao
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
| | - Shaopeng Sun
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
| | - Xiang-dong Li
- Group of Cell Motility and Muscle Contraction, State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of SciencesBeijingChina
- University of Chinese Academy of SciencesBeijingChina
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3
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Myung CH, Jo CS, Hwang JS. Phosphorylation of glucocorticoid receptor induced by 16-kauren-2-beta-18, 19-triol decreases expression of Melanophilin through JNK signalling. Exp Dermatol 2023; 32:1394-1401. [PMID: 37218931 DOI: 10.1111/exd.14837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 04/29/2023] [Accepted: 05/09/2023] [Indexed: 05/24/2023]
Abstract
16-kauren-2-beta-18, 19-triol (16-kauren) is a natural diterpenoid substance derived from Asteraceae psiadia punctulata, a small tropical shrub in Africa and Asia, and it can reduce Mlph expression without affecting the expression of Rab27a and MyoVa in melanocytes. Melanophilin (Mlph) is an important linker protein in the melanosome transport process. However, the signal transduction pathway for the regulation of Mlph expression has not been fully established. We examined the mechanism of 16-kauren on Mlph expression. Murine melan-a melanocytes were used for in vitro analysis. Western blot analysis, quantitative real-time polymerase chain reaction, and luciferase assay were performed. The inhibition of Mlph expression by 16-kauren-2β-18,19-triol (16-kauren) occurs through the JNK signal and is reversed following glucocorticoid receptor (GR) activation by dexamethasone (Dex). Especially, 16-kauren activates JNK and c-jun signalling, part of the MAPK pathway, with subsequent Mlph repression. When the JNK signal is weakened by siRNA, the inhibition of Mlph expression by 16-kauren was not seen. JNK activation by 16-kauren induces GR phosphorylation, which leads to Mlph repression. These results demonstrate that 16-kauren regulates Mlph expression through the phosphorylation of GR via the JNK signalling pathway.
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Affiliation(s)
- Cheol-Hwan Myung
- Department of Genetic & Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, Korea
| | - Chan-Song Jo
- Department of Genetic & Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, Korea
| | - Jae-Sung Hwang
- Department of Genetic & Biotechnology, Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, Korea
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4
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Fernandes B, Cavaco-Paulo A, Matamá T. A Comprehensive Review of Mammalian Pigmentation: Paving the Way for Innovative Hair Colour-Changing Cosmetics. BIOLOGY 2023; 12:biology12020290. [PMID: 36829566 PMCID: PMC9953601 DOI: 10.3390/biology12020290] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/26/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
The natural colour of hair shafts is formed at the bulb of hair follicles, and it is coupled to the hair growth cycle. Three critical processes must happen for efficient pigmentation: (1) melanosome biogenesis in neural crest-derived melanocytes, (2) the biochemical synthesis of melanins (melanogenesis) inside melanosomes, and (3) the transfer of melanin granules to surrounding pre-cortical keratinocytes for their incorporation into nascent hair fibres. All these steps are under complex genetic control. The array of natural hair colour shades are ascribed to polymorphisms in several pigmentary genes. A myriad of factors acting via autocrine, paracrine, and endocrine mechanisms also contributes for hair colour diversity. Given the enormous social and cosmetic importance attributed to hair colour, hair dyeing is today a common practice. Nonetheless, the adverse effects of the long-term usage of such cosmetic procedures demand the development of new methods for colour change. In this context, case reports of hair lightening, darkening and repigmentation as a side-effect of the therapeutic usage of many drugs substantiate the possibility to tune hair colour by interfering with the biology of follicular pigmentary units. By scrutinizing mammalian pigmentation, this review pinpoints key targetable processes for the development of innovative cosmetics that can safely change the hair colour from the inside out.
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Affiliation(s)
- Bruno Fernandes
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
| | - Artur Cavaco-Paulo
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
- LABBELS—Associate Laboratory, 4710-057 Braga, Portugal
- Correspondence: (A.C.-P.); (T.M.); Tel.: +351-253-604-409 (A.C.-P.); +351-253-601-599 (T.M.)
| | - Teresa Matamá
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
- LABBELS—Associate Laboratory, 4710-057 Braga, Portugal
- Correspondence: (A.C.-P.); (T.M.); Tel.: +351-253-604-409 (A.C.-P.); +351-253-601-599 (T.M.)
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5
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Hong C, Yang L, Zhang Y, Li Y, Wu H. Epimedium brevicornum Maxim. Extract exhibits pigmentation by melanin biosynthesis and melanosome biogenesis/transfer. Front Pharmacol 2022; 13:963160. [PMID: 36249817 PMCID: PMC9557186 DOI: 10.3389/fphar.2022.963160] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
Epimedium brevicornum Maxim. (Epimedii Folium) is a traditional medicine widely utilized in China for sexual dysfunction and osteoporosis treatment. Recently, studies have reported that Epimedium flavonoid icariin displayed hair growth and melanogenic ability by targeting tyrosinase activity. Nevertheless, icariin hydrolysate icariside II and icaritin cause depigmentation due to their tyrosinase inhibition. These pigment functional discrepancies from Epimedium constituents arouse our great interest. Then, this study focused on the pigmentation effects of Epimedii Folium extract (EFE) on melanin synthesis and melanosome biogenesis/transfer, and further identified the bioactive constituents. First, in in vitro systemic studies, we discovered that the potent melanogenic and repigmented effects of EFE were dependent on concentration and amount of time in multi-melanocytes, normal human skin tissue, and vitiligo perilesional areas. In vivo, EFE exhibited repigmented effect on two kinds of depigmented models of N-phenylthiourea-induced zebrafish and hydroquinone-induced mice. Mechanistically, EFE strongly promoted tyrosinase activity and upregulated the protein expression of tyrosinase families which finally contribute to melanin biosynthesis by activating the MAPK/ERK1/2 signal pathway. In addition, EFE effectively increased melanosome number, accelerated melanosome maturity and cytoplasmic transport through the growth/extension of melanocyte dendrites, and induced melanosome transfer from melanocyte to keratinocyte for pigmentation. The six main flavonoid ingredients were identified among EFE. Compared to others, epimedin B (EB) was confirmed as a high-content, low-toxicity, and effective melanogenic compound in EFE. Taking all these together, this study systematically demonstrates the potential pigmentation effect of Epimedium brevicornum Maxim., and clarifies its related molecular mechanisms and melanogenesis basis. These results give additional insight into Epimedium herb pharmacology and may provide a novel therapy basis for hypopigmentation disorders.
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Affiliation(s)
- Chen Hong
- Department of TCM Chemistry, School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lili Yang
- Department of Dermatology, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yifan Zhang
- Department of TCM Chemistry, School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yiming Li
- Department of TCM Chemistry, School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- *Correspondence: Huali Wu, ; Yiming Li,
| | - Huali Wu
- Department of TCM Chemistry, School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
- *Correspondence: Huali Wu, ; Yiming Li,
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6
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Chow SYA, Nakayama K, Osaki T, Sugiyama M, Yamada M, Takeuchi H, Ikeuchi Y. Human sensory neurons modulate melanocytes through secretion of RGMB. Cell Rep 2022; 40:111366. [PMID: 36130522 DOI: 10.1016/j.celrep.2022.111366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 05/24/2022] [Accepted: 08/25/2022] [Indexed: 11/03/2022] Open
Abstract
Melanocytes are surrounded by diverse cells, including sensory neurons in our skin, but their interaction and functional importance have been poorly investigated. In this study, we find that melanocytes and nociceptive neurons contact more in human skin color patch tissue than control. Co-culture with human iPSC-derived sensory neurons significantly induces morphogenesis and pigmentation of human melanocytes. To reveal melanocyte-stimulating factors secreted from neurons, we perform proteomic analyses and identify RGMB in the sensory neuron-conditioned medium. RGMB protein induces morphogenesis and melanin production of melanocytes, demonstrating that RGMB is a melanocyte-stimulating factor released from sensory neurons. Transcriptome analysis suggests that the melanosome transport machinery can be controlled by RGMB, leading us to identify the vesicle production response of melanocytes upon RGMB treatment. This study discovers a role of sensory neurons in modulating multiple aspects of human melanocytes through secretion of a key factor: RGMB.
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Affiliation(s)
- Siu Yu A Chow
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan; Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Kazuki Nakayama
- Frontier Research Center, POLA Chemical Industries, Inc., Kanagawa, Japan
| | - Tatsuya Osaki
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan; Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan
| | - Maki Sugiyama
- Frontier Research Center, POLA Chemical Industries, Inc., Kanagawa, Japan
| | - Maiko Yamada
- Frontier Research Center, POLA Chemical Industries, Inc., Kanagawa, Japan
| | - Hirotaka Takeuchi
- Frontier Research Center, POLA Chemical Industries, Inc., Kanagawa, Japan
| | - Yoshiho Ikeuchi
- Institute of Industrial Science, The University of Tokyo, Tokyo, Japan; Department of Chemistry and Biotechnology, School of Engineering, The University of Tokyo, Tokyo, Japan; Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan.
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7
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Bowman DM, Kaji I, Goldenring JR. Altered MYO5B Function Underlies Microvillus Inclusion Disease: Opportunities for Intervention at a Cellular Level. Cell Mol Gastroenterol Hepatol 2022; 14:553-565. [PMID: 35660026 PMCID: PMC9304615 DOI: 10.1016/j.jcmgh.2022.04.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/31/2022] [Accepted: 04/29/2022] [Indexed: 12/10/2022]
Abstract
Microvillus inclusion disease (MVID) is a congenital diarrheal disorder resulting in life-threatening secretory diarrhea in newborns. Inactivating and nonsense mutations in myosin Vb (MYO5B) have been identified in MVID patients. Work using patient tissues, cell lines, mice, and pigs has led to critical insights into the pathology of MVID and a better understanding of both apical trafficking in intestinal enterocytes and intestinal stem cell differentiation. These studies have demonstrated that loss of MYO5B or inactivating mutations lead to loss of apical sodium and water transporters, without loss of apical CFTR, accounting for the major pathology of the disease. In addition, loss of MYO5B expression induces the formation of microvillus inclusions through apical bulk endocytosis that utilizes dynamin and PACSIN2 and recruits tight junction proteins to the sites of bulk endosome formation. Importantly, formation of microvillus inclusions is not required for the induction of diarrhea. Recent investigations have demonstrated that administration of lysophosphatidic acid (LPA) can partially reestablish apical ion transporters in enterocytes of MYO5B KO mice. In addition, further studies have shown that MYO5B loss induces an imbalance in Wnt/Notch signaling pathways that can lead to alterations in enterocyte maturation and tuft cell lineage differentiation. Inhibition of Notch signaling leads to improvements in those cell differentiation deficits. These studies demonstrate that directed strategies through LPA receptor activation and Notch inhibition can bypass the inhibitory effects of MYO5B loss. Thus, effective strategies may be successful in MVID patients and other congenital diarrhea syndromes to reestablish proper apical membrane absorption of sodium and water in enterocytes and ameliorate life-threatening congenital diarrhea.
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Affiliation(s)
- Deanna M Bowman
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Izumi Kaji
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee; Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee.
| | - James R Goldenring
- Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, Tennessee; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee; Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, Tennessee; Nashville VA Medical Center, Nashville, Tennessee.
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8
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Myung CH, Lee JE, Jo CS, Park JI, Hwang JS. Regulation of Melanophilin (Mlph) gene expression by the glucocorticoid receptor (GR). Sci Rep 2021; 11:16813. [PMID: 34413386 PMCID: PMC8376885 DOI: 10.1038/s41598-021-96276-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023] Open
Abstract
Mlph plays a crucial role in regulating skin pigmentation through the melanosome transport process. Although Mlph is a major component involved in melanosome transport, the mechanism that regulates the expression of the Mlph gene has not been identified. In this study, we demonstrate that Mlph expression is regulated by the glucocorticoid receptor (GR). Alteration of GR activity using a specific GR agonist or antagonist only regulated the expression of Mlph among the 3 key melanosome transport proteins. Translocation of GR from the cytosol into the nucleus following Dex treatment was confirmed by separating the cytosol and nuclear fractions and by immunofluorescence staining. In ChIP assays, Dex induced GR binding to the Mlph promoter and we determined that Dex induced the GR binding motif on the Mlph promoter. Our findings contribute to understanding the regulation of Mlph expression and to the novel role of GR in Mlph gene expression.
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Affiliation(s)
- Cheol Hwan Myung
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Gyeonggi-do, 17104, Republic of Korea
| | - Ji Eun Lee
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Gyeonggi-do, 17104, Republic of Korea
| | - Chan Song Jo
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Gyeonggi-do, 17104, Republic of Korea
| | - Jong Il Park
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Gyeonggi-do, 17104, Republic of Korea
| | - Jae Sung Hwang
- Department of Genetic Engineering & Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Gyeonggi-do, 17104, Republic of Korea.
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9
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Castellano-Pellicena I, Morrison CG, Bell M, O’Connor C, Tobin DJ. Melanin Distribution in Human Skin: Influence of Cytoskeletal, Polarity, and Centrosome-Related Machinery of Stratum basale Keratinocytes. Int J Mol Sci 2021; 22:ijms22063143. [PMID: 33808676 PMCID: PMC8003549 DOI: 10.3390/ijms22063143] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/13/2021] [Accepted: 03/14/2021] [Indexed: 12/12/2022] Open
Abstract
Melanin granules cluster within supra-nuclear caps in basal keratinocytes (KCs) of the human epidermis, where they protect KC genomic DNA against ultraviolet radiation (UVR) damage. While much is known about melanogenesis in melanocytes (MCs) and a moderate amount about melanin transfer from MC to KC, we know little about the fate of melanin once inside KCs. We recently reported that melanin fate in progenitor KCs is regulated by rare asymmetric organelle movement during mitosis. Here, we explore the role of actin, microtubules, and centrosome-associated machinery in distributing melanin within KCs. Short-term cultures of human skin explants were treated with cytochalasin-B and nocodazole to target actin filaments and microtubules, respectively. Treatment effects on melanin distribution were assessed by the Warthin-Starry stain, on centrosome-associated proteins by immunofluorescence microscopy, and on co-localisation with melanin granules by brightfield microscopy. Cytochalasin-B treatment disassembled supra-nuclear melanin caps, while nocodazole treatment moved melanin from the apical to basal KC domain. Centrosome and centriolar satellite-associated proteins showed a high degree of co-localisation with melanin. Thus, once melanin granules are transferred to KCs, their preferred apical distribution appears to be facilitated by coordinated movement of centrosomes and centriolar satellites. This mechanism may control melanin's strategic position within UVR-exposed KCs.
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Affiliation(s)
- Irene Castellano-Pellicena
- The Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland;
| | - Ciaran G. Morrison
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, H91 W2TY Galway, Ireland;
| | - Mike Bell
- Walgreens Boots Alliance, Nottingham NG90 1BS, UK; (M.B.); (C.O.)
| | - Clare O’Connor
- Walgreens Boots Alliance, Nottingham NG90 1BS, UK; (M.B.); (C.O.)
| | - Desmond J. Tobin
- The Charles Institute of Dermatology, School of Medicine, University College Dublin, D04 V1W8 Dublin, Ireland;
- The Conway Institute of Biomolecular and Biomedical Research, University College Dublin, D04 V1W8 Dublin, Ireland
- Correspondence: ; Tel.: +353-(0)-1-716-6262
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10
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Bowman SL, Bi-Karchin J, Le L, Marks MS. The road to lysosome-related organelles: Insights from Hermansky-Pudlak syndrome and other rare diseases. Traffic 2020; 20:404-435. [PMID: 30945407 DOI: 10.1111/tra.12646] [Citation(s) in RCA: 120] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/02/2019] [Accepted: 04/02/2019] [Indexed: 12/11/2022]
Abstract
Lysosome-related organelles (LROs) comprise a diverse group of cell type-specific, membrane-bound subcellular organelles that derive at least in part from the endolysosomal system but that have unique contents, morphologies and functions to support specific physiological roles. They include: melanosomes that provide pigment to our eyes and skin; alpha and dense granules in platelets, and lytic granules in cytotoxic T cells and natural killer cells, which release effectors to regulate hemostasis and immunity; and distinct classes of lamellar bodies in lung epithelial cells and keratinocytes that support lung plasticity and skin lubrication. The formation, maturation and/or secretion of subsets of LROs are dysfunctional or entirely absent in a number of hereditary syndromic disorders, including in particular the Hermansky-Pudlak syndromes. This review provides a comprehensive overview of LROs in humans and model organisms and presents our current understanding of how the products of genes that are defective in heritable diseases impact their formation, motility and ultimate secretion.
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Affiliation(s)
- Shanna L Bowman
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jing Bi-Karchin
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Linh Le
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Cell and Molecular Biology Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Michael S Marks
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia Research Institute, Philadelphia, Pennsylvania.,Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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11
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Yamada H, Hakozaki M, Uemura A, Yamashita T. Effect of fatty acids on melanogenesis and tumor cell growth in melanoma cells. J Lipid Res 2019; 60:1491-1502. [PMID: 31345992 PMCID: PMC6718436 DOI: 10.1194/jlr.m090712] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Revised: 07/12/2019] [Indexed: 11/20/2022] Open
Abstract
Fatty acids have various physiological effects on melanoma. For example, palmitic acid (PA) increases melanin levels; linoleic acid and DHA decrease melanin levels; and DHA suppresses tumor growth. In this study, we focused on the relationship between the structure of fatty acids and their physiological effects in melanoma to examine the likely mechanisms of action. We showed that saturated fatty acids and PUFAs display opposing effects on melanin content in melanoma cells. Likewise, PA and EPA have opposing effects in terms of actin polymerization. Our findings suggest that PA and EPA change melanin content in melanoma to alter melanosome trafficking by modulating actin polymerization. Here, we also examined the mechanism of the anti-tumor effect of DHA. We found that DHA interacts with receptor for activated C kinase 1 and represses melanoma cell proliferation by suppressing protein kinase C signaling. Our results suggest a new mechanism to explain the physiological effects of fatty acids.
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Affiliation(s)
- Hidetoshi Yamada
- Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003, Japan.
| | - Mayuka Hakozaki
- Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003, Japan
| | - Aiko Uemura
- Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003, Japan
| | - Tetsuro Yamashita
- Department of Biological Chemistry and Food Sciences Faculty of Agriculture, Iwate University, Morioka, Iwate 020-8550, Japan
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12
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Myosin Va and spermine synthase: partners in exosome transport. Biosci Rep 2019; 39:BSR20190326. [PMID: 30967493 PMCID: PMC6488853 DOI: 10.1042/bsr20190326] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 11/21/2022] Open
Abstract
A recent paper in Bioscience Reports (BSR20182189) describes the discovery of an
interaction between the motor protein myosin Va and the metabolic enzyme
spermine synthase. Myosin Va is a molecular motor which plays a key role in
vesicle transport. Mutations in the gene which encodes this protein are
associated with Griscelli syndrome type 1 and the ‘dilute’
phenotype in animals. Spermine synthase catalyzes the conversion of spermidine
to spermine. This largely cytoplasmic enzyme can also be localized to the
soluble fraction in exosomes. Mutations in the spermine synthase gene are
associated with Snyder Robinson mental retardation syndrome. The interaction
between the two proteins was detected using the yeast two hybrid method and
verified by microscale thermophoresis of recombinant proteins. Knockdown of the
MYO5A gene reduced the expression of mRNA coding for
spermine synthase. The amount of this transcript was also reduced in cells
derived from a patient with Griscelli syndrome type 1. This suggests that, in
addition to a direct physical interaction between the two proteins, myosin Va
also modulates the transcription of the spermine synthase gene. The mechanism
for this modulation is currently unknown. These findings have implications for
Griscelli syndrome type 1 and Snyder Robinson mental retardation syndrome. They
also suggest that interactions between myosin Va and soluble exosome proteins
such as spermine synthase may be important in the mechanism of exosome
transport.
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13
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Robinson CL, Evans RD, Sivarasa K, Ramalho JS, Briggs DA, Hume AN. The adaptor protein melanophilin regulates dynamic myosin-Va:cargo interaction and dendrite development in melanocytes. Mol Biol Cell 2019; 30:742-752. [PMID: 30699046 PMCID: PMC6589771 DOI: 10.1091/mbc.e18-04-0237] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The regulation of organelle transport by the cytoskeleton is fundamental for eukaryotic survival. Cytoskeleton motors are typically modular proteins with conserved motor and diverse cargo-binding domains. Motor:cargo interactions are often indirect and mediated by adaptor proteins, for example, Rab GTPases. Rab27a, via effector melanophilin (Mlph), recruits myosin-Va (MyoVa) to melanosomes and thereby disperses them into melanocyte dendrites. To better understand how adaptors regulate motor:cargo interaction, we used single melanosome fluorescence recovery after photobleaching (smFRAP) to characterize the association kinetics among MyoVa, its adaptors, and melanosomes. We found that MyoVa and Mlph rapidly recovered after smFRAP, whereas Rab27a did not, indicating that MyoVa and Mlph dynamically associate with melanosomes and Rab27a does not. This suggests that dynamic Rab27a:effector interaction rather than Rab27a melanosome:cytosol cycling regulates MyoVa:melanosome association. Accordingly, a Mlph-Rab27a fusion protein reduced MyoVa smFRAP, indicating that it stabilized melanosomal MyoVa. Finally, we tested the functional importance of dynamic MyoVa:melanosome interaction. We found that whereas a MyoVa-Rab27a fusion protein dispersed melanosomes in MyoVa-deficient cells, dendrites were significantly less elongated than in wild-type cells. Given that dendrites are the prime sites of melanosome transfer from melanocytes to keratinocytes, we suggest that dynamic MyoVa:melanosome interaction is important for pigmentation in vivo.
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Affiliation(s)
| | - Richard D Evans
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
| | - Kajana Sivarasa
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
| | - Jose S Ramalho
- CEDOC Faculdade de Ciencias Medicas, Universidade Nova de Lisboa, 1169-056 Lisbon, Portugal
| | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
| | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, United Kingdom
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14
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Gardini L, Heissler SM, Arbore C, Yang Y, Sellers JR, Pavone FS, Capitanio M. Dissecting myosin-5B mechanosensitivity and calcium regulation at the single molecule level. Nat Commun 2018; 9:2844. [PMID: 30030431 PMCID: PMC6054644 DOI: 10.1038/s41467-018-05251-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 06/22/2018] [Indexed: 11/08/2022] Open
Abstract
Myosin-5B is one of three members of the myosin-5 family of actin-based molecular motors. Despite its fundamental role in recycling endosome trafficking and in collective actin network dynamics, the molecular mechanisms underlying its motility are inherently unknown. Here we combine single-molecule imaging and high-speed laser tweezers to dissect the mechanoenzymatic properties of myosin-5B. We show that a single myosin-5B moves processively in 36-nm steps, stalls at ~2 pN resistive forces, and reverses its directionality at forces >2 pN. Interestingly, myosin-5B mechanosensitivity differs from that of myosin-5A, while it is strikingly similar to kinesin-1. In particular, myosin-5B run length is markedly and asymmetrically sensitive to force, a property that might be central to motor ensemble coordination. Furthermore, we show that Ca2+ does not affect the enzymatic activity of the motor unit, but abolishes myosin-5B processivity through calmodulin dissociation, providing important insights into the regulation of postsynaptic cargoes trafficking in neuronal cells.
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Affiliation(s)
- Lucia Gardini
- LENS-European Laboratory for Non-linear Spectroscopy, University of Florence, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
- National Institute of Optics-National Research Council, Largo Fermi 6, 50125, Florence, Italy
| | - Sarah M Heissler
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892-8015, USA
| | - Claudia Arbore
- LENS-European Laboratory for Non-linear Spectroscopy, University of Florence, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019, Sesto Fiorentino, Italy
| | - Yi Yang
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892-8015, USA
- Hunan Provincial Key Laboratory of Protein Engineering in Animal Vaccines, Hunan Agricultural University, Changsha, Hunan, 410128, China
| | - James R Sellers
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892-8015, USA
| | - Francesco S Pavone
- LENS-European Laboratory for Non-linear Spectroscopy, University of Florence, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy
- National Institute of Optics-National Research Council, Largo Fermi 6, 50125, Florence, Italy
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019, Sesto Fiorentino, Italy
| | - Marco Capitanio
- LENS-European Laboratory for Non-linear Spectroscopy, University of Florence, Via Nello Carrara 1, 50019, Sesto Fiorentino, Italy.
- Department of Physics and Astronomy, University of Florence, Via Sansone 1, 50019, Sesto Fiorentino, Italy.
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15
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Koike S, Yamasaki K, Yamauchi T, Inoue M, Shimada-Ohmori R, Tsuchiyama K, Aiba S. Toll-like receptors 2 and 3 enhance melanogenesis and melanosome transport in human melanocytes. Pigment Cell Melanoma Res 2018; 31:570-584. [PMID: 29603875 DOI: 10.1111/pcmr.12703] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 03/18/2018] [Indexed: 01/18/2023]
Abstract
Because little is known about how the innate immune response influences skin pigmentation, we examined whether Toll-like receptor (TLR) agonists participate in melanogenesis and melanosome transportation. We observed that TLR2/2 agonist HKLM and TLR3 agonist Poly(I:C) increased the amount of extracellular melanin from primary human epidermal melanocytes. HKLM, but not Poly(I:C), increased the melanogenic genes such as tyrosinase and dopachrome tautomerase. Poly(I:C) increased the expression of Rab27A, a molecule that facilitates melanosome transport to perimembranous actin filament. UVB irradiation induced Rab27A and melanosome transportation in a similar manner of Poly(I:C). SiRNA for TLR3 or Rab27A suppressed the perimembranous accumulation of Gp100-positive vesicles in melanocytes and decreased melanin transfer to neighboring keratinocytes induced by both Poly(I:C) and UVB. These results suggest that the microenvironment in the epidermis and innate immune stimuli, such as microbiome and ultraviolet represented here by TLR2 and TLR3 agonists, could affect the melanogenesis in human melanocytes.
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Affiliation(s)
- Saaya Koike
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kenshi Yamasaki
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Takeshi Yamauchi
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Mai Inoue
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryoko Shimada-Ohmori
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Kenichiro Tsuchiyama
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Setsuya Aiba
- Department of Dermatology, Tohoku University Graduate School of Medicine, Sendai, Japan
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16
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Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2017; 9:158-181. [PMID: 29239692 DOI: 10.1080/21541248.2017.1397833] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
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Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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17
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Heissler SM, Chinthalapudi K, Sellers JR. Kinetic signatures of myosin-5B, the motor involved in microvillus inclusion disease. J Biol Chem 2017; 292:18372-18385. [PMID: 28882893 DOI: 10.1074/jbc.m117.801456] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Revised: 08/29/2017] [Indexed: 11/06/2022] Open
Abstract
Myosin-5B is a ubiquitous molecular motor that transports cargo vesicles of the endomembrane system in intracellular recycling pathways. Myosin-5B malfunction causes the congenital enteropathy microvillus inclusion disease, underlining its importance in cellular homeostasis. Here we describe the interaction of myosin-5B with F-actin, nucleotides, and the pyrazolopyrimidine compound myoVin-1. We show that single-headed myosin-5B is an intermediate duty ratio motor with a kinetic ATPase cycle that is rate-limited by the release of phosphate. The presence of a second head generates strain and gating in the myosin-5B dimer that alters the kinetic signature by reducing the actin-activated ADP release rate to become rate-limiting. This kinetic transition into a high-duty ratio motor is a prerequisite for the proposed transport function of myosin-5B in cellular recycling pathways. Moreover, we show that the small molecule compound myoVin-1 inhibits the enzymatic and functional activity of myosin-5B in vitro Partial inhibition of the actin-activated steady-state ATPase activity and sliding velocity suggests that caution should be used when probing the effect of myoVin-1 on myosin-5-dependent transport processes in cells.
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Affiliation(s)
- Sarah M Heissler
- From the Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-8015 and
| | - Krishna Chinthalapudi
- the Cell Adhesion Laboratory, Department of Integrative Structural and Computational Biology, Scripps Research Institute, Jupiter, Florida 33458
| | - James R Sellers
- From the Laboratory of Molecular Physiology, NHLBI, National Institutes of Health, Bethesda, Maryland 20892-8015 and
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18
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Bonifacino JS, Neefjes J. Moving and positioning the endolysosomal system. Curr Opin Cell Biol 2017; 47:1-8. [PMID: 28231489 PMCID: PMC5537022 DOI: 10.1016/j.ceb.2017.01.008] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 01/28/2017] [Accepted: 01/30/2017] [Indexed: 12/18/2022]
Abstract
The endolysosomal system is extremely dynamic, yet highly organized. The spatio-temporal distribution of endolysosomal organelles depends on transport driven by microtubule motors such as kinesins and dynein, and by actin-based myosin motors. It has recently become appreciated that interactions with motors are controlled by contacts with other organelles, particularly the endoplasmic reticulum (ER). The ER also controls the concentration of endolysosomal organelles in the perinuclear area, as well as their fission and fusion, through a complex system of tethering proteins. Dynamic interactions go both ways, as contacts with endosomes can influence the movement of the ER and peroxisomes. The dynamics of endolysosomal organelles should thus no longer be studied in isolation, but in the context of the whole endomembrane system.
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Affiliation(s)
- Juan S Bonifacino
- Cell Biology and Neurobiology Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Jacques Neefjes
- Department of Chemical Immunology, Leiden University Medical Center LUMC, Einthovenweg 20, 2333 ZC Leiden, The Netherlands.
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19
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Dieckmann NMG, Frazer GL, Asano Y, Stinchcombe JC, Griffiths GM. The cytotoxic T lymphocyte immune synapse at a glance. J Cell Sci 2017; 129:2881-6. [PMID: 27505426 DOI: 10.1242/jcs.186205] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The immune synapse provides an important structure for communication with immune cells. Studies on immune synapses formed by cytotoxic T lymphocytes (CTLs) highlight the dynamic changes and specialised mechanisms required to facilitate focal signalling and polarised secretion in immune cells. In this Cell Science at a Glance article and the accompanying poster, we illustrate the different steps that reveal the specialised mechanisms used to focus secretion at the CTL immune synapse and allow CTLs to be such efficient and precise serial killers.
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Affiliation(s)
- Nele M G Dieckmann
- Cambridge Institute for Medical Research, Biomedical Campus, Cambridge CB2 0XY, UK
| | - Gordon L Frazer
- Cambridge Institute for Medical Research, Biomedical Campus, Cambridge CB2 0XY, UK
| | - Yukako Asano
- Cambridge Institute for Medical Research, Biomedical Campus, Cambridge CB2 0XY, UK
| | - Jane C Stinchcombe
- Cambridge Institute for Medical Research, Biomedical Campus, Cambridge CB2 0XY, UK
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, Biomedical Campus, Cambridge CB2 0XY, UK
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20
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Mao L, Wang H, Ma F, Guo Z, He H, Zhou H, Wang N. Exposure to static magnetic fields increases insulin secretion in rat INS-1 cells by activating the transcription of the insulin gene and up-regulating the expression of vesicle-secreted proteins. Int J Radiat Biol 2017; 93:831-840. [PMID: 28593826 DOI: 10.1080/09553002.2017.1332439] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE To evaluate the effect of static magnetic fields (SMFs) on insulin secretion and explore the mechanisms underlying exposure to SMF-induced insulin secretion in rat insulinoma INS-1 cells. MATERIALS AND METHODS INS-1 cells were exposed to a 400 mT SMF for 72 h, and the proliferation of INS-1 cells was detected by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The secretion of insulin was measured with an enzyme linked immunosorbent assays (ELISA), the expression of genes was detected by real-time PCR, and the expression of proteins was measured by Western blotting. RESULTS Exposure to an SMF increased the expression and secretion of insulin by INS-1 cells but did not affect cell proliferation. Moreover, SMF exposure up-regulated the expression of several pancreas-specific transcriptional factors. Specifically, the activity of the rat insulin promoter was enhanced in INS-1 cells exposed to an SMF, and the expression levels of synaptosomal-associated protein 25 (SNAP-25) and syntaxin-1A were up-regulated after exposure to an SMF. CONCLUSIONS SMF exposure can promote insulin secretion in rat INS-1 cells by activating the transcription of the insulin gene and up-regulating the expression of vesicle-secreted proteins.
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Affiliation(s)
- Libin Mao
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
| | - Huiqin Wang
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
| | - Fenghui Ma
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
| | - Zhixia Guo
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
| | - Hongpeng He
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
| | - Hao Zhou
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
| | - Nan Wang
- a Key Laboratory of Industrial Fermentation Microbiology, Ministry of Education and Tianjin, College of Biotechnology , Tianjin University of Science and Technology , Tianjin , P.R. China
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21
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Myosin Va's adaptor protein melanophilin enforces track selection on the microtubule and actin networks in vitro. Proc Natl Acad Sci U S A 2017; 114:E4714-E4723. [PMID: 28559319 DOI: 10.1073/pnas.1619473114] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pigment organelles, or melanosomes, are transported by kinesin, dynein, and myosin motors. As such, melanosome transport is an excellent model system to study the functional relationship between the microtubule- and actin-based transport systems. In mammalian melanocytes, it is well known that the Rab27a/melanophilin/myosin Va complex mediates actin-based transport in vivo. However, pathways that regulate the overall directionality of melanosomes on the actin/microtubule networks have not yet been delineated. Here, we investigated the role of PKA-dependent phosphorylation on the activity of the actin-based Rab27a/melanophilin/myosin Va transport complex in vitro. We found that melanophilin, specifically its C-terminal actin-binding domain (ABD), is a target of PKA. Notably, in vitro phosphorylation of the ABD closely recapitulated the previously described in vivo phosphorylation pattern. Unexpectedly, we found that phosphorylation of the ABD affected neither the interaction of the complex with actin nor its movement along actin tracks. Surprisingly, the phosphorylation state of melanophilin was instead important for reversible association with microtubules in vitro. Dephosphorylated melanophilin preferred binding to microtubules even in the presence of actin, whereas phosphorylated melanophilin associated with actin. Indeed, when actin and microtubules were present simultaneously, melanophilin's phosphorylation state enforced track selection of the Rab27a/melanophilin/myosin Va transport complex. Collectively, our results unmasked the regulatory dominance of the melanophilin adaptor protein over its associated motor and offer an unexpected mechanism by which filaments of the cytoskeletal network compete for the moving organelles to accomplish directional transport on the cytoskeleton in vivo.
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22
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Cheeseman LP, Boulanger J, Bond LM, Schuh M. Two pathways regulate cortical granule translocation to prevent polyspermy in mouse oocytes. Nat Commun 2016; 7:13726. [PMID: 27991490 PMCID: PMC5187413 DOI: 10.1038/ncomms13726] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Accepted: 10/27/2016] [Indexed: 12/20/2022] Open
Abstract
An egg must be fertilized by a single sperm only. To prevent polyspermy, the zona pellucida, a structure that surrounds mammalian eggs, becomes impermeable upon fertilization, preventing the entry of further sperm. The structural changes in the zona upon fertilization are driven by the exocytosis of cortical granules. These translocate from the oocyte's centre to the plasma membrane during meiosis. However, very little is known about the mechanism of cortical granule translocation. Here we investigate cortical granule transport and dynamics in live mammalian oocytes by using Rab27a as a marker. We show that two separate mechanisms drive their transport: myosin Va-dependent movement along actin filaments, and an unexpected vesicle hitchhiking mechanism by which cortical granules bind to Rab11a vesicles powered by myosin Vb. Inhibiting cortical granule translocation severely impaired the block to sperm entry, suggesting that translocation defects could contribute to miscarriages that are caused by polyspermy.
Mammalian eggs release cortical granules to avoid being fertilized by more than a single sperm as polyspermy results in nonviable embryos. Here, the authors describe the mechanism driving translocation of the granules to the cortex in the mouse egg and show this process is essential to prevent polyspermy.
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Affiliation(s)
- Liam P Cheeseman
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Jérôme Boulanger
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Lisa M Bond
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK
| | - Melina Schuh
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, UK.,Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Göttingen 37077, Germany
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23
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MYO5A Gene Is a Target of MITF in Melanocytes. J Invest Dermatol 2016; 137:985-989. [PMID: 27939378 DOI: 10.1016/j.jid.2016.11.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 11/09/2016] [Accepted: 11/09/2016] [Indexed: 11/21/2022]
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24
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Abstract
Many cells of the myeloid lineage use an unusual secretory organelle to deliver their effector mechanisms. In these cells, the lysosomal compartment is often modified not only to fulfill the degradative functions of a lysosome but also as a mechanism for secreting additional proteins that are found in the lysosomes of each specialized cell type. These extra proteins vary from one cell type to another according to the specialized function of the cell. For example, mast cells package histamine; cytotoxic T cells express perforin; azurophilic granules in neutrophils express antimicrobial peptides, and platelets von Willebrand factor. Upon release, these very different proteins can trigger inflammation, cell lysis, microbial death, and clotting, respectively, and hence deliver the very different effector mechanisms of these different myeloid cells.
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25
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Mangan AJ, Sietsema DV, Li D, Moore JK, Citi S, Prekeris R. Cingulin and actin mediate midbody-dependent apical lumen formation during polarization of epithelial cells. Nat Commun 2016; 7:12426. [PMID: 27484926 PMCID: PMC4976216 DOI: 10.1038/ncomms12426] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 07/01/2016] [Indexed: 12/26/2022] Open
Abstract
Coordinated polarization of epithelial cells is a key step during morphogenesis that leads to the formation of an apical lumen. Rab11 and its interacting protein FIP5 are necessary for the targeting of apical endosomes to the midbody and apical membrane initiation site (AMIS) during lumenogenesis. However, the machinery that mediates AMIS establishment and FIP5-endosome targeting remains unknown. Here we identify a FIP5-interacting protein, Cingulin, which localizes to the AMIS and functions as a tether mediating FIP5-endosome targeting. We analysed the machinery mediating AMIS recruitment to the midbody and determined that both branched actin and microtubules are required for establishing the site of the nascent lumen. We demonstrate that the Rac1-WAVE/Scar complex mediates Cingulin recruitment to the AMIS by inducing branched actin formation, and that Cingulin directly binds to microtubule C-terminal tails through electrostatic interactions. We propose a new mechanism for apical endosome targeting and AMIS formation around the midbody during epithelial lumenogenesis. Polarisation of epithelial cells causes lumen formation, which is mediated by apical membrane initiation site (AMIS) and FIP5, but how this is regulated is unclear. Here, the authors identify cingulin as a FIP-5 interacting protein, recruiting the Rac1-WAVE/Scar complex to the AMIS and branched actin formation.
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Affiliation(s)
- Anthony J Mangan
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Daniel V Sietsema
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Dongying Li
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
| | - Sandra Citi
- Cell Biology Department, University of Geneva, CH-1211 GENEVA 4, Switzerland
| | - Rytis Prekeris
- Department of Cell and Developmental Biology, School of Medicine, Anschutz Medical Campus, University of Colorado Denver, Aurora, Colorado 80045, USA
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Sinha S, Hoshino D, Hong NH, Kirkbride KC, Grega-Larson NE, Seiki M, Tyska MJ, Weaver AM. Cortactin promotes exosome secretion by controlling branched actin dynamics. J Cell Biol 2016; 214:197-213. [PMID: 27402952 PMCID: PMC4949450 DOI: 10.1083/jcb.201601025] [Citation(s) in RCA: 211] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 06/28/2016] [Indexed: 12/11/2022] Open
Abstract
Exosomes are extracellular vesicles that influence cellular behavior and enhance cancer aggressiveness by carrying bioactive molecules. The mechanisms that regulate exosome secretion are poorly understood. Here, we show that the actin cytoskeletal regulatory protein cortactin promotes exosome secretion. Knockdown or overexpression of cortactin in cancer cells leads to a respective decrease or increase in exosome secretion, without altering exosome cargo content. Live-cell imaging revealed that cortactin controls both trafficking and plasma membrane docking of multivesicular late endosomes (MVEs). Regulation of exosome secretion by cortactin requires binding to the branched actin nucleating Arp2/3 complex and to actin filaments. Furthermore, cortactin, Rab27a, and coronin 1b coordinately control stability of cortical actin MVE docking sites and exosome secretion. Functionally, the addition of purified exosomes to cortactin-knockdown cells rescued defects of those cells in serum-independent growth and invasion. These data suggest a model in which cortactin promotes exosome secretion by stabilizing cortical actin-rich MVE docking sites.
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Affiliation(s)
- Seema Sinha
- Department of Cancer Biology, Vanderbilt University Medical School, Nashville, TN 37232
| | | | - Nan Hyung Hong
- Department of Cancer Biology, Vanderbilt University Medical School, Nashville, TN 37232
| | - Kellye C Kirkbride
- Department of Cancer Biology, Vanderbilt University Medical School, Nashville, TN 37232
| | - Nathan E Grega-Larson
- Department of Cell and Developmental Biology, Vanderbilt University Medical School, Nashville, TN 37232
| | - Motoharu Seiki
- Division of Cancer Cell Research, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Matthew J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical School, Nashville, TN 37232
| | - Alissa M Weaver
- Department of Cancer Biology, Vanderbilt University Medical School, Nashville, TN 37232 Department of Cell and Developmental Biology, Vanderbilt University Medical School, Nashville, TN 37232 Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232
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Abstract
The myosin holoenzyme is a multimeric protein complex consisting of heavy chains and light chains. Myosin light chains are calmodulin family members which are crucially involved in the mechanoenzymatic function of the myosin holoenzyme. This review examines the diversity of light chains within the myosin superfamily, discusses interactions between the light chain and the myosin heavy chain as well as regulatory and structural functions of the light chain as a subunit of the myosin holoenzyme. It covers aspects of the myosin light chain in the localization of the myosin holoenzyme, protein-protein interactions and light chain binding to non-myosin binding partners. Finally, this review challenges the dogma that myosin regulatory and essential light chain exclusively associate with conventional myosin heavy chains while unconventional myosin heavy chains usually associate with calmodulin.
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Affiliation(s)
- Sarah M Heissler
- a Laboratory of Molecular Physiology; National Heart, Lung, and Blood Institute; National Institutes of Health ; Bethesda , MD USA
| | - James R Sellers
- a Laboratory of Molecular Physiology; National Heart, Lung, and Blood Institute; National Institutes of Health ; Bethesda , MD USA
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Abstract
Melanin is responsible for pigmentation of skin and hair and is synthesized in a specialized organelle, the melanosome, in melanocytes. A genome-wide association study revealed that the two pore segment channel 2 (TPCN2) gene is strongly linked to pigmentation variations. TPCN2 encodes the two-pore channel 2 (TPC2) protein, a cation channel. Nevertheless, how TPC2 regulates pigmentation remains unknown. Here, we show that TPC2 is expressed in melanocytes and localizes to the melanosome-limiting membrane and, to a lesser extent, to endolysosomal compartments by confocal fluorescence and immunogold electron microscopy. Immunomagnetic isolation of TPC2-containing organelles confirmed its coresidence with melanosomal markers. TPCN2 knockout by means of clustered regularly interspaced short palindromic repeat/CRISPR-associated 9 gene editing elicited a dramatic increase in pigment content in MNT-1 melanocytic cells. This effect was rescued by transient expression of TPC2-GFP. Consistently, siRNA-mediated knockdown of TPC2 also caused a substantial increase in melanin content in both MNT-1 cells and primary human melanocytes. Using a newly developed genetically encoded pH sensor targeted to melanosomes, we determined that the melanosome lumen in TPC2-KO MNT-1 cells and primary melanocytes subjected to TPC2 knockdown is less acidic than in control cells. Fluorescence and electron microscopy analysis revealed that TPC2-KO MNT-1 cells have significantly larger melanosomes than control cells, but the number of organelles is unchanged. TPC2 likely regulates melanosomes pH and size by mediating Ca(2+) release from the organelle, which is decreased in TPC2-KO MNT-1 cells, as determined with the Ca(2+) sensor tyrosinase-GCaMP6. Thus, our data show that TPC2 regulates pigmentation through two fundamental determinants of melanosome function: pH and size.
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Heissler SM, Sellers JR. Kinetic Adaptations of Myosins for Their Diverse Cellular Functions. Traffic 2016; 17:839-59. [PMID: 26929436 DOI: 10.1111/tra.12388] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 02/25/2016] [Accepted: 02/25/2016] [Indexed: 12/18/2022]
Abstract
Members of the myosin superfamily are involved in all aspects of eukaryotic life. Their function ranges from the transport of organelles and cargos to the generation of membrane tension, and the contraction of muscle. The diversity of physiological functions is remarkable, given that all enzymatically active myosins follow a conserved mechanoenzymatic cycle in which the hydrolysis of ATP to ADP and inorganic phosphate is coupled to either actin-based transport or tethering of actin to defined cellular compartments. Kinetic capacities and limitations of a myosin are determined by the extent to which actin can accelerate the hydrolysis of ATP and the release of the hydrolysis products and are indispensably linked to its physiological tasks. This review focuses on kinetic competencies that - together with structural adaptations - result in myosins with unique mechanoenzymatic properties targeted to their diverse cellular functions.
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Affiliation(s)
- Sarah M Heissler
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, B50/3523, Bethesda, MD 20892-8015, USA
| | - James R Sellers
- Laboratory of Molecular Physiology, National Heart, Lung, and Blood Institute, National Institutes of Health, 50 South Drive, B50/3523, Bethesda, MD 20892-8015, USA
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Heissler SM, Sellers JR. Various Themes of Myosin Regulation. J Mol Biol 2016; 428:1927-46. [PMID: 26827725 DOI: 10.1016/j.jmb.2016.01.022] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/12/2016] [Accepted: 01/19/2016] [Indexed: 10/24/2022]
Abstract
Members of the myosin superfamily are actin-based molecular motors that are indispensable for cellular homeostasis. The vast functional and structural diversity of myosins accounts for the variety and complexity of the underlying allosteric regulatory mechanisms that determine the activation or inhibition of myosin motor activity and enable precise timing and spatial aspects of myosin function at the cellular level. This review focuses on the molecular basis of posttranslational regulation of eukaryotic myosins from different classes across species by allosteric intrinsic and extrinsic effectors. First, we highlight the impact of heavy and light chain phosphorylation. Second, we outline intramolecular regulatory mechanisms such as autoinhibition and subsequent activation. Third, we discuss diverse extramolecular allosteric mechanisms ranging from actin-linked regulatory mechanisms to myosin:cargo interactions. At last, we briefly outline the allosteric regulation of myosins with synthetic compounds.
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Affiliation(s)
- Sarah M Heissler
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Drive, B50/3529, Bethesda, MD 20892-8015, USA.
| | - James R Sellers
- Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, 50 South Drive, B50/3529, Bethesda, MD 20892-8015, USA
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Burgoyne T, O'Connor MN, Seabra MC, Cutler DF, Futter CE. Regulation of melanosome number, shape and movement in the zebrafish retinal pigment epithelium by OA1 and PMEL. J Cell Sci 2015; 128:1400-7. [PMID: 25690007 PMCID: PMC4379728 DOI: 10.1242/jcs.164400] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Analysis of melanosome biogenesis in the retinal pigment epithelium (RPE) is challenging because it occurs predominantly in a short embryonic time window. Here, we show that the zebrafish provides an ideal model system for studying this process because in the RPE the timing of melanosome biogenesis facilitates molecular manipulation using morpholinos. Morpholino-mediated knockdown of OA1 (also known as GPR143), mutations in the human homologue of which cause the most common form of human ocular albinism, induces a major reduction in melanosome number, recapitulating a key feature of the mammalian disease where reduced melanosome numbers precede macromelanosome formation. We further show that PMEL, a key component of mammalian melanosome biogenesis, is required for the generation of cylindrical melanosomes in zebrafish, which in turn is required for melanosome movement into the apical processes and maintenance of photoreceptor integrity. Spherical and cylindrical melanosomes containing similar melanin volumes co-exist in the cell body but only cylindrical melanosomes enter the apical processes. Taken together, our findings indicate that melanosome number and shape are independently regulated and that melanosome shape controls a function in the RPE that depends on localisation in the apical processes.
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Affiliation(s)
| | - Marie N O'Connor
- UCL Institute of Ophthalmology, London EC1V 9EL, UK MRC Laboratory for Molecular Cell Biology, University College, London WC1E 6BT, UK
| | | | - Daniel F Cutler
- MRC Laboratory for Molecular Cell Biology, University College, London WC1E 6BT, UK
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Abstract
Rab proteins represent the largest branch of the Ras-like small GTPase superfamily and there are 66 Rab genes in the human genome. They alternate between GTP- and GDP-bound states, which are facilitated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), and function as molecular switches in regulation of intracellular membrane trafficking in all eukaryotic cells. Each Rab targets to an organelle and specify a transport step along exocytic, endocytic, and recycling pathways as well as the crosstalk between these pathways. Through interactions with multiple effectors temporally, a Rab can control membrane budding and formation of transport vesicles, vesicle movement along cytoskeleton, and membrane fusion at the target compartment. The large number of Rab proteins reflects the complexity of the intracellular transport system, which is essential for the localization and function of membrane and secretory proteins such as hormones, growth factors, and their membrane receptors. As such, Rab proteins have emerged as important regulators for signal transduction, cell growth, and differentiation. Altered Rab expression and/or activity have been implicated in diseases ranging from neurological disorders, diabetes to cancer.
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Affiliation(s)
- Guangpu Li
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, 975 NE 10 Street, BRC 417, Oklahoma City, OK, 73104, USA,
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Bultema JJ, Boyle JA, Malenke PB, Martin FE, Dell'Angelica EC, Cheney RE, Di Pietro SM. Myosin vc interacts with Rab32 and Rab38 proteins and works in the biogenesis and secretion of melanosomes. J Biol Chem 2014; 289:33513-28. [PMID: 25324551 DOI: 10.1074/jbc.m114.578948] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Class V myosins are actin-based motors with conserved functions in vesicle and organelle trafficking. Herein we report the discovery of a function for Myosin Vc in melanosome biogenesis as an effector of melanosome-associated Rab GTPases. We isolated Myosin Vc in a yeast two-hybrid screening for proteins that interact with Rab38, a Rab protein involved in the biogenesis of melanosomes and other lysosome-related organelles. Rab38 and its close homolog Rab32 bind to Myosin Vc but not to Myosin Va or Myosin Vb. Binding depends on residues in the switch II region of Rab32 and Rab38 and regions of the Myosin Vc coiled-coil tail domain. Myosin Vc also interacts with Rab7a and Rab8a but not with Rab11, Rab17, and Rab27. Although Myosin Vc is not particularly abundant on pigmented melanosomes, its knockdown in MNT-1 melanocytes caused defects in the trafficking of integral membrane proteins to melanosomes with substantially increased surface expression of Tyrp1, nearly complete loss of Tyrp2, and significant Vamp7 mislocalization. Knockdown of Myosin Vc in MNT-1 cells more than doubled the abundance of pigmented melanosomes but did not change the number of unpigmented melanosomes. Together the data demonstrate a novel role for Myosin Vc in melanosome biogenesis and secretion.
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Affiliation(s)
- Jarred J Bultema
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, the Department of Chemistry and Biochemistry, University of Colorado, Colorado Springs, Colorado Springs, Colorado 80918
| | - Judith A Boyle
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Parker B Malenke
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Faye E Martin
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Esteban C Dell'Angelica
- the Department of Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, California 90095, and
| | - Richard E Cheney
- the Department of Cell Biology and Physiology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Santiago M Di Pietro
- From the Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523,
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Patients with Griscelli syndrome and normal pigmentation identify RAB27A mutations that selectively disrupt MUNC13-4 binding. J Allergy Clin Immunol 2014; 135:1310-8.e1. [PMID: 25312756 PMCID: PMC4418747 DOI: 10.1016/j.jaci.2014.08.039] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/23/2014] [Accepted: 08/27/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND Familial hemophagocytic lymphohistiocytosis (FHL) is a rare and often fatal disorder characterized by defective cellular cytotoxicity and hyperinflammation, and the only cure known to date is hematopoietic stem cell transplantation. Mutations in RAB27A, LYST, and AP3B1 give rise to FHL associated with oculocutaneous albinism, and patients with FHL are usually only screened for mutations in these genes when albinism is observed. A number of patients with FHL and normal pigmentation remain without a genetic diagnosis. OBJECTIVE We asked whether patients with FHL with immunodeficiency but with normal pigmentation might sometimes have mutations that affected cellular cytotoxicity without affecting pigmentation. METHODS We carried out mutation analysis of RAB27A, LYST, and AP3B1 in patients with FHL with pigment dilution, as well as a cohort with no clinical evidence of pigment dilution but no mutations in the other known FHL-related genes (PRF1, STXBP2, and UNC13D). RESULTS We identify patients with Griscelli syndrome type 2 with biallelic mutations in RAB27A in the absence of albinism. All 6 patients carried mutations at amino acids R141, Y159, or S163 of Rab27a that disrupt the interaction of Rab27a with Munc13-4, without impairing the interaction between melanophilin and Rab27a. CONCLUSION These studies highlight the need for RAB27A sequencing in patients with FHL with normal pigmentation and identify a critical binding site for Munc13-4 on Rab27a, revealing the molecular basis of this interaction.
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Myosin Vb mediated plasma membrane homeostasis regulates peridermal cell size and maintains tissue homeostasis in the zebrafish epidermis. PLoS Genet 2014; 10:e1004614. [PMID: 25233349 PMCID: PMC4169241 DOI: 10.1371/journal.pgen.1004614] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 07/18/2014] [Indexed: 12/31/2022] Open
Abstract
The epidermis is a stratified epithelium, which forms a barrier to maintain the internal milieu in metazoans. Being the outermost tissue, growth of the epidermis has to be strictly coordinated with the growth of the embryo. The key parameters that determine tissue growth are cell number and cell size. So far, it has remained unclear how the size of epidermal cells is maintained and whether it contributes towards epidermal homeostasis. We have used genetic analysis in combination with cellular imaging to show that zebrafish goosepimples/myosin Vb regulates plasma membrane homeostasis and is involved in maintenance of cell size in the periderm, the outermost epidermal layer. The decrease in peridermal cell size in Myosin Vb deficient embryos is compensated by an increase in cell number whereas decrease in cell number results in the expansion of peridermal cells, which requires myosin Vb (myoVb) function. Inhibition of cell proliferation as well as cell size expansion results in increased lethality in larval stages suggesting that this two-way compensatory mechanism is essential for growing larvae. Our analyses unravel the importance of Myosin Vb dependent cell size regulation in epidermal homeostasis and demonstrate that the epidermis has the ability to maintain a dynamic balance between cell size and cell number.
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Evans RD, Robinson C, Briggs DA, Tooth DJ, Ramalho JS, Cantero M, Montoliu L, Patel S, Sviderskaya EV, Hume AN. Myosin-Va and dynamic actin oppose microtubules to drive long-range organelle transport. Curr Biol 2014; 24:1743-50. [PMID: 25065759 PMCID: PMC4131108 DOI: 10.1016/j.cub.2014.06.019] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 05/06/2014] [Accepted: 06/10/2014] [Indexed: 02/04/2023]
Abstract
In animal cells, microtubule and actin tracks and their associated motors (dynein, kinesin, and myosin) are thought to regulate long- and short-range transport, respectively. Consistent with this, microtubules extend from the perinuclear centrosome to the plasma membrane and allow bidirectional cargo transport over long distances (>1 μm). In contrast, actin often comprises a complex network of short randomly oriented filaments, suggesting that myosin motors move cargo short distances. These observations underpin the "highways and local roads" model for transport along microtubule and actin tracks. The "cooperative capture" model exemplifies this view and suggests that melanosome distribution in melanocyte dendrites is maintained by long-range transport on microtubules followed by actin/myosin-Va-dependent tethering. In this study, we used cell normalization technology to quantitatively examine the contribution of microtubules and actin/myosin-Va to organelle distribution in melanocytes. Surprisingly, our results indicate that microtubules are essential for centripetal, but not centrifugal, transport. Instead, we find that microtubules retard a centrifugal transport process that is dependent on myosin-Va and a population of dynamic F-actin. Functional analysis of mutant proteins indicates that myosin-Va works as a transporter dispersing melanosomes along actin tracks whose +/barbed ends are oriented toward the plasma membrane. Overall, our data highlight the role of myosin-Va and actin in transport, and not tethering, and suggest a new model in which organelle distribution is determined by the balance between microtubule-dependent centripetal and myosin-Va/actin-dependent centrifugal transport. These observations appear to be consistent with evidence coming from other systems showing that actin/myosin networks can drive long-distance organelle transport and positioning.
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Affiliation(s)
- Richard D Evans
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | | | - Deborah A Briggs
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - David J Tooth
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK
| | - Jose S Ramalho
- CEDOC Faculdade de Ciencias Medicas, Universidade Nova de Lisboa, 1169-056 Lisbon, Portugal
| | - Marta Cantero
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid 28049, Spain; CIBERER-ISCIII, Madrid 28029, Spain
| | - Lluis Montoliu
- Centro Nacional de Biotecnologia (CNB-CSIC), Madrid 28049, Spain; CIBERER-ISCIII, Madrid 28029, Spain
| | - Shyamal Patel
- Cell Signalling Research Centre, Division of Biomedical Sciences, St. George's, University of London, London SW17 0RE, UK
| | - Elena V Sviderskaya
- Cell Signalling Research Centre, Division of Biomedical Sciences, St. George's, University of London, London SW17 0RE, UK
| | - Alistair N Hume
- School of Life Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
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Tarafder AK, Bolasco G, Correia MS, Pereira FJC, Iannone L, Hume AN, Kirkpatrick N, Picardo M, Torrisi MR, Rodrigues IP, Ramalho JS, Futter CE, Barral DC, Seabra MC. Rab11b mediates melanin transfer between donor melanocytes and acceptor keratinocytes via coupled exo/endocytosis. J Invest Dermatol 2014; 134:1056-1066. [PMID: 24141907 DOI: 10.1038/jid.2013.432] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 08/30/2013] [Accepted: 09/17/2013] [Indexed: 12/30/2022]
Abstract
The transfer of melanin from melanocytes to keratinocytes is a crucial process underlying maintenance of skin pigmentation and photoprotection against UV damage. Here, we present evidence supporting coupled exocytosis of the melanin core, or melanocore, by melanocytes and subsequent endocytosis by keratinocytes as a predominant mechanism of melanin transfer. Electron microscopy analysis of human skin samples revealed three lines of evidence supporting this: (1) the presence of melanocores in the extracellular space; (2) within keratinocytes, melanin was surrounded by a single membrane; and (3) this membrane lacked the melanosomal membrane protein tyrosinase-related protein 1 (TYRP1). Moreover, co-culture of melanocytes and keratinocytes suggests that melanin exocytosis is specifically induced by keratinocytes. Furthermore, depletion of Rab11b, but not Rab27a, caused a marked decrease in both keratinocyte-stimulated melanin exocytosis and transfer to keratinocytes. Thus, we propose that the predominant mechanism of melanin transfer is keratinocyte-induced exocytosis, mediated by Rab11b through remodeling of the melanosome membrane, followed by subsequent endocytosis by keratinocytes.
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Affiliation(s)
- Abul K Tarafder
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal; Molecular Medicine, National Heart and Lung Institute, Imperial College London, London, UK
| | - Giulia Bolasco
- Molecular Medicine, National Heart and Lung Institute, Imperial College London, London, UK
| | - Maria S Correia
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Francisco J C Pereira
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Lucio Iannone
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Alistair N Hume
- Molecular Medicine, National Heart and Lung Institute, Imperial College London, London, UK
| | - Niall Kirkpatrick
- Craniofacial and Orbito-Palpebral Surgery Unit at Chelsea and Westminster Hospital, London, UK
| | - Mauro Picardo
- Laboratorio di Fisiopatologia Cutanea, Istituto Dermatologico San Gallicano, IFO, Rome, Italy
| | - Maria R Torrisi
- Laboratorio di Fisiopatologia Cutanea, Istituto Dermatologico San Gallicano, IFO, Rome, Italy; Dipartimento di Medicina Clinica e Molecolare, Azienda Ospedaliera Sant'Andrea, Università di Roma 'La Sapienza', Rome, Italy
| | - Inês P Rodrigues
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - José S Ramalho
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Clare E Futter
- Institute of Ophthalmology, University College London, London, UK
| | - Duarte C Barral
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.
| | - Miguel C Seabra
- CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal; Instituto Gulbenkian de Ciência, Oeiras, Portugal; Molecular Medicine, National Heart and Lung Institute, Imperial College London, London, UK.
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Blanco-Sánchez B, Clément A, Fierro J, Washbourne P, Westerfield M. Complexes of Usher proteins preassemble at the endoplasmic reticulum and are required for trafficking and ER homeostasis. Dis Model Mech 2014; 7:547-59. [PMID: 24626987 PMCID: PMC4007406 DOI: 10.1242/dmm.014068] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Usher syndrome (USH), the leading cause of hereditary combined hearing and vision loss, is characterized by sensorineural deafness and progressive retinal degeneration. Mutations in several different genes produce USH, but the proximal cause of sensory cell death remains mysterious. We adapted a proximity ligation assay to analyze associations among three of the USH proteins, Cdh23, Harmonin and Myo7aa, and the microtubule-based transporter Ift88 in zebrafish inner ear mechanosensory hair cells. We found that the proteins are in close enough proximity to form complexes and that these complexes preassemble at the endoplasmic reticulum (ER). Defects in any one of the three USH proteins disrupt formation and trafficking of the complex and result in diminished levels of the other proteins, generalized trafficking defects and ER stress that triggers apoptosis. ER stress, thus, contributes to sensory hair cell loss and provides a new target to explore for protective therapies for USH.
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Ishida M, Arai SP, Ohbayashi N, Fukuda M. The GTPase-deficient Rab27A(Q78L) mutant inhibits melanosome transport in melanocytes through trapping of Rab27A effector protein Slac2-a/melanophilin in their cytosol: development of a novel melanosome-targetinG tag. J Biol Chem 2014; 289:11059-11067. [PMID: 24584932 DOI: 10.1074/jbc.m114.552281] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The small GTPase Rab27A is a crucial regulator of actin-based melanosome transport in melanocytes, and functionally defective Rab27A causes human Griscelli syndrome type 2, which is characterized by silvery hair. A GTPase-deficient, constitutively active Rab27A(Q78L) mutant has been shown to act as an inhibitor of melanosome transport and to induce perinuclear aggregation of melanosomes, but the molecular mechanism by which Rab27A(Q78L) inhibits melanosome transport remained to be determined. In this study, we attempted to identify the primary cause of the perinuclear melanosome aggregation induced by Rab27A(Q78L). The results showed that Rab27A(Q78L) is unable to localize on mature melanosomes and that its inhibitory activity on melanosome transport is completely dependent on its binding to the Rab27A effector Slac2-a/melanophilin. When we forcibly expressed Rab27A(Q78L) on mature melanosomes by using a novel melanosome-targeting tag that we developed in this study and named the MST tag, the MST-Rab27A(Q78L) fusion protein behaved in the same manner as wild-type Rab27A. It localized on mature melanosomes without inducing melanosome aggregation and restored normal peripheral melanosome distribution in Rab27A-deficient cells. These findings indicate that the GTPase activity of Rab27A is required for its melanosome localization but is not required for melanosome transport.
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Affiliation(s)
- Morié Ishida
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Saki P Arai
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Norihiko Ohbayashi
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
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Sun Y, Chiu TT, Foley KP, Bilan PJ, Klip A. Myosin Va mediates Rab8A-regulated GLUT4 vesicle exocytosis in insulin-stimulated muscle cells. Mol Biol Cell 2014; 25:1159-70. [PMID: 24478457 PMCID: PMC3967978 DOI: 10.1091/mbc.e13-08-0493] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Rab-GTPases are important molecular switches regulating intracellular vesicle traffic, and we recently showed that Rab8A and Rab13 are activated by insulin in muscle to mobilize GLUT4-containing vesicles to the muscle cell surface. Here we show that the unconventional motor protein myosin Va (MyoVa) is an effector of Rab8A in this process. In CHO-IR cell lysates, a glutathione S-transferase chimera of the cargo-binding COOH tail (CT) of MyoVa binds Rab8A and the related Rab10, but not Rab13. Binding to Rab8A is stimulated by insulin in a phosphatidylinositol 3-kinase-dependent manner, whereas Rab10 binding is insulin insensitive. MyoVa-CT preferentially binds GTP-locked Rab8A. Full-length green fluorescent protein (GFP)-MyoVa colocalizes with mCherry-Rab8A in perinuclear small puncta, whereas GFP-MyoVa-CT collapses the GTPase into enlarged perinuclear depots. Further, GFP-MyoVa-CT blocks insulin-stimulated translocation of exofacially myc-tagged GLUT4 to the surface of muscle cells. Mutation of amino acids in MyoVa-CT predicted to bind Rab8A abrogates both interaction with Rab8A (not Rab10) and inhibition of insulin-stimulated GLUT4myc translocation. Of importance, small interfering RNA-mediated MyoVa silencing reduces insulin-stimulated GLUT4myc translocation. Rab8A colocalizes with GLUT4 in perinuclear but not submembrane regions visualized by confocal total internal reflection fluorescence microscopy. Hence insulin signaling to the molecular switch Rab8A connects with the motor protein MyoVa to mobilize GLUT4 vesicles toward the muscle cell plasma membrane.
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Affiliation(s)
- Yi Sun
- Cell Biology Program, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
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41
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Schafer JC, Baetz NW, Lapierre LA, McRae RE, Roland JT, Goldenring JR. Rab11-FIP2 interaction with MYO5B regulates movement of Rab11a-containing recycling vesicles. Traffic 2014; 15:292-308. [PMID: 24372966 DOI: 10.1111/tra.12146] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2013] [Revised: 12/17/2013] [Accepted: 12/24/2013] [Indexed: 12/28/2022]
Abstract
A tripartite association of Rab11a with both Rab11-FIP2 and MYO5B regulates recycling endosome trafficking. We sought to define the intermolecular interactions required between Rab11-FIP2 and MYO5B. Using a random mutagenesis strategy, we identified point mutations at S229P or G233E in Rab11-FIP2 that caused loss of interaction with MYO5B in yeast two-hybrid assays as well as loss of interaction of Rab11-FIP2(129-356) with MYO5B tail when expressed in HeLa cells. Single mutations or the double S229P/G233E mutation failed to alter the association of full-length Rab11-FIP2 with MYO5B tail in HeLa cells. While EGFP-Rab11-FIP2 wild type colocalized with endogenous MYO5B staining in MDCK cells, EGFP-Rab11-FIP2(S229P/G233E) showed a significant decrease in localization with endogenous MYO5B. Analysis of Rab11a-containing vesicle movement in live HeLa cells demonstrated that when the MYO5B/Rab11-FIP2 association is perturbed by mutation or by Rab11-FIP2 knockdown, vesicle movement is increased in both speed and track length, consistent with an impairment of MYO5B tethering at the cytoskeleton. These results support a critical role for the interaction of MYO5B with Rab11-FIP2 in stabilizing the functional complex with Rab11a, which regulates dynamic movements of membrane recycling vesicles.
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Affiliation(s)
- Jenny C Schafer
- Section of Surgical Sciences and the Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN, USA
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42
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Abstract
It has been over 30 years since the reorganization of both the microtubule network and a 'peculiar actin polarization' was reported at the contact area of cytotoxic T lymphocytes interacting with target cells. Since that time, hundreds of studies have been published in an effort to elucidate the structure and function of the microtubule network and the actin cytoskeleton in T-cell activation, migration, and effector function at the interface between a T cell and its cognate antigen-presenting cell or target cell. This interface has become known as the immunological synapse, and this review examines some of the roles played by the cytoskeleton at the synapse.
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Affiliation(s)
- Alex T Ritter
- Cambridge Institute for Medical Research, University of Cambridge Biomedical CampusCambridge, UK
| | - Karen L Angus
- Cambridge Institute for Medical Research, University of Cambridge Biomedical CampusCambridge, UK
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, University of Cambridge Biomedical CampusCambridge, UK
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43
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Sckolnick M, Krementsova EB, Warshaw DM, Trybus KM. More than just a cargo adapter, melanophilin prolongs and slows processive runs of myosin Va. J Biol Chem 2013; 288:29313-22. [PMID: 23979131 DOI: 10.1074/jbc.m113.476929] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin Va (myoVa) is a molecular motor that processively transports cargo along actin tracks. One well studied cargo in vivo is the melanosome, a pigment organelle that is moved first by kinesin on microtubules and then handed off to myoVa for transport in the actin-rich dendritic periphery of melanocytes. Melanophilin (Mlph) is the adapter protein that links Rab27a-melanosomes to myoVa. Using total internal reflection fluorescence microscopy and quantum dot-labeled full-length myoVa, we show at the single-molecule level that Mlph increases the number of processively moving myoVa motors by 17-fold. Surprisingly, myoVa-Mlph moves ~4-fold slower than myoVa alone and with twice the run length. These two changes greatly increase the time spent on actin, a property likely to enhance the transfer of melanosomes to the adjacent keratinocyte. In contrast to the variable stepping pattern of full-length myoVa, the myoVa-Mlph complex shows a normal gating pattern between the heads typical of a fully active motor and consistent with a cargo-dependent activation mechanism. The Mlph-dependent changes in myoVa depend on a positively charged cluster of amino acids in the actin binding domain of Mlph, suggesting that Mlph acts as a "tether" that links the motor to the track. Our results provide a molecular explanation for the uncharacteristically slow speed of melanosome movement by myoVa in vivo. More generally, these data show that proteins that link motors to cargo can modify motor properties to enhance their biological role.
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Affiliation(s)
- Maria Sckolnick
- From the Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont 05405
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44
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Seixas E, Barros M, Seabra MC, Barral DC. Rab and Arf proteins in genetic diseases. Traffic 2013; 14:871-85. [PMID: 23565987 DOI: 10.1111/tra.12072] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Revised: 04/03/2013] [Accepted: 04/08/2013] [Indexed: 01/29/2023]
Abstract
Rab and ADP-ribosylation factor (Arf) family proteins are master regulators of membrane trafficking and are involved in all steps of vesicular transport. These families of small guanine-nucleotide-binding (G) proteins are well suited to regulate membrane trafficking processes since their nucleotide state determines their conformation and the capacity to bind to a multitude of effectors, which mediate their functions. In recent years, several inherited diseases have been associated with mutations in genes encoding proteins belonging to these two families or in proteins that regulate their GTP-binding cycle. The genetic diseases that are caused by defects in Rabs, Arfs or their regulatory proteins are heterogeneous and display diverse symptoms. However, these diseases mainly affect two types of subcellular compartments, namely lysosome-related organelles and cilia. Also, several of these diseases affect the nervous system. Thus, the study of these diseases represents an opportunity to understand their etiology and the molecular mechanisms involved, as well as to develop novel therapeutic strategies.
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Affiliation(s)
- Elsa Seixas
- CEDOC, Faculdade de Ciências Médicas, FCM, Universidade Nova de Lisboa, 1169-056, Lisboa, Portugal
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45
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Sitaram A, Marks MS. Mechanisms of protein delivery to melanosomes in pigment cells. Physiology (Bethesda) 2012; 27:85-99. [PMID: 22505665 DOI: 10.1152/physiol.00043.2011] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Vertebrate pigment cells in the eye and skin are useful models for cell types that use specialized endosomal trafficking pathways to partition cargo proteins to unique lysosome-related organelles such as melanosomes. This review describes current models of protein trafficking required for melanosome biogenesis in mammalian melanocytes.
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Affiliation(s)
- Anand Sitaram
- Cell and Molecular Biology Graduate Group, Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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46
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Hirvonen MJ, Mulari MTK, Büki KG, Vihko P, Härkönen PL, Väänänen HK. Rab13 is upregulated during osteoclast differentiation and associates with small vesicles revealing polarized distribution in resorbing cells. J Histochem Cytochem 2012; 60:537-49. [PMID: 22562557 DOI: 10.1369/0022155412448069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Osteoclasts are bone-resorbing multinucleated cells that undergo drastic changes in their polarization due to heavy vesicular trafficking during the resorption cycle. These events require the precise orchestration of membrane traffic in order to maintain the unique characteristics of the different membrane domains in osteoclasts. Rab proteins are small GTPases involved in regulation of most, if not all, steps of vesicle trafficking. The investigators studied RAB genes in human osteoclasts and found that at least 26 RABs were expressed in osteoclasts. Out of these, RAB13 gene expression was highly upregulated during differentiation of human peripheral blood monocytic cells into osteoclasts. To study its possible function in osteoclasts, the investigators performed immunolocalization studies for Rab13 and various known markers of osteoclast vesicular trafficking. Rab13 localized to small vesicular structures at the superior parts of the osteoclast between the trans-Golgi network and basolateral membrane domain. Rab13 localization suggests that it is not involved in endocytosis or transcytosis of bone degradation products. In addition, Rab13 did not associate with early endosomes or recycling endosomes labeled with EEA1 or TRITC-conjugated transferrin, respectively. Its involvement in glucose transporter traffic was excluded as well. It is suggested that Rab13 is associated with a putative secretory function in osteoclasts.
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Affiliation(s)
- Mirkka J Hirvonen
- Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku, Turku, Finland.
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47
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Direct imaging of RAB27B-enriched secretory vesicle biogenesis in lacrimal acinar cells reveals origins on a nascent vesicle budding site. PLoS One 2012; 7:e31789. [PMID: 22363735 PMCID: PMC3282733 DOI: 10.1371/journal.pone.0031789] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 01/16/2012] [Indexed: 12/20/2022] Open
Abstract
This study uses YFP-tagged Rab27b expression in rabbit lacrimal gland acinar cells, which are polarized secretory epithelial cells, to characterize early stages of secretory vesicle trafficking. Here we demonstrate the utility of YFP-Rab27b to delineate new perspectives on the mechanisms of early vesicle biogenesis in lacrimal gland acinar cells, where information is significantly limited. Protocols were developed to deplete the mature YFP-Rab27b-enriched secretory vesicle pool in the subapical region of the cell, and confocal fluorescence microscopy was used to track vesicle replenishment. This analysis revealed a basally-localized organelle, which we termed the "nascent vesicle site," from which nascent vesicles appeared to emerge. Subapical vesicular YFP-Rab27b was co-localized with p150(Glued), a component of the dynactin cofactor of cytoplasmic dynein. Treatment with the microtubule-targeted agent, nocodazole, did not affect release of mature secretory vesicles, although during vesicle repletion it significantly altered nascent YFP-Rab27b-enriched secretory vesicle localization. Instead of moving to the subapical region, these vesicles were trapped at the nascent vesicle site which was adjacent to, if not a sub-compartment of, the trans-Golgi network. Finally, YFP-Rab27b-enriched secretory vesicles which reached the subapical cytoplasm appeared to acquire the actin-based motor protein, Myosin 5C. Our findings show that Rab27b enrichment occurs early in secretory vesicle formation, that secretory vesicles bud from a visually discernable nascent vesicle site, and that transport from the nascent vesicle site to the subapical region requires intact microtubules.
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48
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Abstract
Advances in live-cell microscopy have revealed the extraordinarily dynamic nature of intracellular organelles. Moreover, movement appears to be critical in establishing and maintaining intracellular organization and organellar and cellular function. Motility is regulated by the activity of organelle-associated motor proteins, kinesins, dyneins and myosins, which move cargo along polar MT (microtubule) and actin tracks. However, in most instances, the motors that move specific organelles remain mysterious. Over recent years, pigment granules, or melanosomes, within pigment cells have provided an excellent model for understanding the molecular mechanisms by which motor proteins associate with and move intracellular organelles. In the present paper, we discuss recent discoveries that shed light on the mechanisms of melanosome transport and highlight future prospects for the use of pigment cells in unravelling general molecular mechanisms of intracellular transport.
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49
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Tarafder AK, Wasmeier C, Figueiredo AC, Booth AEG, Orihara A, Ramalho JS, Hume AN, Seabra MC. Rab27a targeting to melanosomes requires nucleotide exchange but not effector binding. Traffic 2011; 12:1056-66. [PMID: 21554507 PMCID: PMC3509405 DOI: 10.1111/j.1600-0854.2011.01216.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rab GTPases are important determinants of organelle identity and regulators of vesicular transport pathways. Consequently, each Rab occupies a highly specific subcellular localization. However, the precise mechanisms governing Rab targeting remain unclear. Guanine nucleotide exchange factors (GEFs), putative membrane-resident targeting factors and effector binding have all been implicated as critical regulators of Rab targeting. Here, we address these issues using Rab27a targeting to melanosomes as a model system. Rab27a regulates motility of lysosome-related organelles and secretory granules. Its effectors have been characterized extensively, and we have identified Rab3GEP as the non-redundant Rab27a GEF in melanocytes (Figueiredo AC et al. Rab3GEP is the non-redundant guanine nucleotide exchange factor for Rab27a in melanocytes. J Biol Chem 2008;283:23209–23216). Using Rab27a mutants that show impaired binding to representatives of all four Rab27a effector subgroups, we present evidence that effector binding is not essential for targeting of Rab27a to melanosomes. In contrast, we observed that knockdown of Rab3GEP resulted in mis-targeting of Rab27a, suggesting that Rab3GEP activity is required for correct targeting of Rab27a. However, the identification of Rab27a mutants that undergo efficient GDP/GTP exchange in the presence of Rab3GEP in vitro but are mis-targeted in a cellular context indicates that nucleotide loading is not the sole determinant of subcellular targeting of Rab27a. Our data support a model in which exchange activity, but not effector binding, represents one essential factor that contributes to membrane targeting of Rab proteins.
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Affiliation(s)
- Abul K Tarafder
- Molecular Medicine, National Heart and Lung Institute (NHLI), Imperial College London, London SW7 2AZ, UK
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50
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Hartman MA, Finan D, Sivaramakrishnan S, Spudich JA. Principles of unconventional myosin function and targeting. Annu Rev Cell Dev Biol 2011; 27:133-55. [PMID: 21639800 DOI: 10.1146/annurev-cellbio-100809-151502] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Unconventional myosins are a superfamily of actin-based motors implicated in diverse cellular processes. In recent years, much progress has been made in describing their biophysical properties, and headway has been made into analyzing their cellular functions. Here, we focus on the principles that guide in vivo motor function and targeting to specific cellular locations. Rather than describe each motor comprehensively, we outline the major themes that emerge from research across the superfamily and use specific examples to illustrate each. In presenting the data in this format, we seek to identify open questions in each field as well as to point out commonalities between them. To advance our understanding of myosins' roles in vivo, clearly we must identify their cellular cargoes and the protein complexes that regulate motor attachment to fully appreciate their functions on the cellular and developmental levels.
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Affiliation(s)
- M Amanda Hartman
- Department of Biochemistry, Stanford University, Stanford, California 94305, USA
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