1
|
O'Donoghue L, Smolenski A. Roles of G proteins and their GTPase-activating proteins in platelets. Biosci Rep 2024; 44:BSR20231420. [PMID: 38808367 PMCID: PMC11139668 DOI: 10.1042/bsr20231420] [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] [Received: 11/17/2023] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/30/2024] Open
Abstract
Platelets are small anucleate blood cells supporting vascular function. They circulate in a quiescent state monitoring the vasculature for injuries. Platelets adhere to injury sites and can be rapidly activated to secrete granules and to form platelet/platelet aggregates. These responses are controlled by signalling networks that include G proteins and their regulatory guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs). Recent proteomics studies have revealed the complete spectrum of G proteins, GEFs, and GAPs present in platelets. Some of these proteins are specific for platelets and very few have been characterised in detail. GEFs and GAPs play a major role in setting local levels of active GTP-bound G proteins in response to activating and inhibitory signals encountered by platelets. Thus, GEFs and GAPs are highly regulated themselves and appear to integrate G protein regulation with other cellular processes. This review focuses on GAPs of small G proteins of the Arf, Rab, Ras, and Rho families, as well as of heterotrimeric G proteins found in platelets.
Collapse
Affiliation(s)
- Lorna O'Donoghue
- UCD School of Medicine, University College Dublin, UCD Conway Institute, Belfield, Dublin 4, Ireland
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green 123, Dublin 2, Ireland
| | - Albert Smolenski
- UCD School of Medicine, University College Dublin, UCD Conway Institute, Belfield, Dublin 4, Ireland
- Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, 123 St. Stephen’s Green 123, Dublin 2, Ireland
| |
Collapse
|
2
|
Wu Z, Que H, Li C, Yan L, Wang S, Rong Y. Rab32 family proteins regulate autophagosomal components recycling. J Cell Biol 2024; 223:e202306040. [PMID: 38323995 PMCID: PMC10849918 DOI: 10.1083/jcb.202306040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 11/06/2023] [Accepted: 12/19/2023] [Indexed: 02/08/2024] Open
Abstract
In autophagy, autophagosomes deliver the lumenal contents to lysosomes for degradation via autophagosome-lysosome fusion. In contrast, autophagosome outer membrane components were recycled via autophagosomal components recycling (ACR), which is mediated by the recycler complex. The recycler complex, composed of SNX4, SNX5, and SNX17, cooperate with the dynein-dynactin complex to mediate ACR. However, how ACR is regulated remains unknown. Here, we found that Rab32 family proteins localize to autolysosomes and are required for ACR, rather than other autophagosomal or lysosomal Rab proteins. The GTPase activity of Rab32 family proteins, governed by their guanine nucleotide exchange factor and GTPase-activating protein, plays a key role in regulating ACR. This regulation occurs through the control of recycler complex formation, as well as the connection between the recycler-cargo and dynactin complex. Together, our study reveals an unidentified Rab32 family-dependent regulatory mechanism for ACR.
Collapse
Affiliation(s)
- Zhe Wu
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Huilin Que
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Chuangpeng Li
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
| | - Li Yan
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shixuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yueguang Rong
- School of Basic Medicine, Tongji Medical College and State Key Laboratory for Diagnosis and Treatment of Severe Zoonotic Infectious Disease, Huazhong University of Science and Technology, Wuhan, China
- Cell Architecture Research Center, Huazhong University of Science and Technology, Wuhan, China
| |
Collapse
|
3
|
Tokuda K, Lu SL, Zhang Z, Kato Y, Chen S, Noda K, Hirose K, Usami Y, Uzawa N, Murakami S, Toyosawa S, Fukuda M, Sun-Wada GH, Wada Y, Noda T. Rab32 and Rab38 maintain bone homeostasis by regulating intracellular traffic in osteoclasts. Cell Struct Funct 2023; 48:223-239. [PMID: 37793839 DOI: 10.1247/csf.23061] [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] [Indexed: 10/06/2023] Open
Abstract
Osteoclasts play a crucial role in bone homeostasis by forming resorption pits on bone surfaces, resulting in bone resorption. The osteoclast expression of Rab38 protein is highly induced during differentiation from macrophages. Here we generated mice with double knockout (DKO) of Rab38 and its paralogue, Rab32, to investigate the roles of these proteins in osteoclasts. Bone marrow-derived macrophages from Rab32/38 DKO mice differentiated normally into osteoclasts in vitro. However, DKO osteoclasts showed reduced bone resorption activity. These osteoclasts also demonstrated defective secretion of tartrate-resistant acid phosphatase and cathepsin K into culture medium. Furthermore, the plasma membrane localization of a3, an osteoclast-specific a subunit of V-ATPase, was abrogated in DKO mice, substantiating the reduced resorption activity. In vivo, Rab32- and Rab38-positive cells were attached to the bone surface. Eight-week-old DKO mice showed significantly thickened trabecular bones in micro-CT and histomorphometry analysis, as well as reduced serum levels of cross-linked C-telopeptide of type I collagen, indicating diminished bone resorption in vivo. In DKO male mice over 10 weeks of age, hyperostosis appeared at the talofibular syndesmosis, the distal junction of the tibia and fibula. Furthermore, middle-aged mice (10 to 12 months of age) exhibited kyphosis, which is not usually observed in wild-type male mice until around 24 months of age. These results indicate that Rab32 and Rab38 contribute to osteoclast function by supporting intracellular traffic, thereby maintaining normal bone homeostasis.Key words: Rab32, Rab38, osteoclast, lysosome-related organelle, secretory lysosome.
Collapse
Affiliation(s)
- Kanako Tokuda
- Graduate School of Frontier Biosciences, Osaka University
| | - Shiou-Ling Lu
- Department of Oral Cellular Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University
| | - Zidi Zhang
- Department of Oral Cellular Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University
| | - Yumiko Kato
- Department of Oral Cellular Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University
- Department of Oral & Maxillofacial Oncology and Surgery, Graduate School of Dentistry, Osaka University
| | - Siyu Chen
- Department of Oral Cellular Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University
| | - Kazuya Noda
- Department of Oral Cellular Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University
- Department of Periodontology and Regenerative Dentistry, Graduate School of Dentistry, Osaka University
| | - Katsutoshi Hirose
- Department of Oral and Maxillofacial Pathology, Graduate School of Dentistry, Osaka University
| | - Yu Usami
- Department of Oral and Maxillofacial Pathology, Graduate School of Dentistry, Osaka University
| | - Narikazu Uzawa
- Department of Oral & Maxillofacial Oncology and Surgery, Graduate School of Dentistry, Osaka University
| | - Shinya Murakami
- Department of Periodontology and Regenerative Dentistry, Graduate School of Dentistry, Osaka University
| | - Satoru Toyosawa
- Department of Oral and Maxillofacial Pathology, Graduate School of Dentistry, Osaka University
| | - Mitsunori Fukuda
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University
| | - Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College
| | - Yoh Wada
- Department of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University
- Center for Infectious Disease Education and Research, Osaka University
| | - Takeshi Noda
- Graduate School of Frontier Biosciences, Osaka University
- Department of Oral Cellular Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University
- Center for Infectious Disease Education and Research, Osaka University
| |
Collapse
|
4
|
Kelliher S, Gamba S, Weiss L, Shen Z, Marchetti M, Schieppati F, Scaife C, Madden S, Bennett K, Fortune A, Maung S, Fay M, Ní Áinle F, Maguire P, Falanga A, Kevane B, Krishnan A. Platelet proteo-transcriptomic profiling validates mediators of thrombosis and proteostasis in patients with myeloproliferative neoplasms. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563619. [PMID: 37961700 PMCID: PMC10634751 DOI: 10.1101/2023.10.23.563619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Patients with chronic Myeloproliferative Neoplasms (MPN) including polycythemia vera (PV) and essential thrombocythemia (ET) exhibit unique clinical features, such as a tendency toward thrombosis and hemorrhage, and risk of disease progression to secondary bone marrow fibrosis and/or acute leukemia. Although an increase in blood cell lineage counts (quantitative features) contribute to these morbid sequelae, the significant qualitative abnormalities of myeloid cells that contribute to vascular risk are not well understood. Here, we address this critical knowledge gap via a comprehensive and untargeted profiling of the platelet proteome in a large (n= 140) cohort of patients (from two independent sites) with an established diagnosis of PV and ET (and complement prior work on the MPN platelet transcriptome from a third site). We discover distinct MPN platelet protein expression and confirm key molecular impairments associated with proteostasis and thrombosis mechanisms of potential relevance to MPN pathology. Specifically, we validate expression of high-priority candidate markers from the platelet transcriptome at the platelet proteome (e.g., calreticulin (CALR), Fc gamma receptor (FcγRIIA) and galectin-1 (LGALS1) pointing to their likely significance in the proinflammatory, prothrombotic and profibrotic phenotypes in patients with MPN. Together, our proteo-transcriptomic study identifies the peripherally-derived platelet molecular profile as a potential window into MPN pathophysiology and demonstrates the value of integrative multi-omic approaches in gaining a better understanding of the complex molecular dynamics of disease.
Collapse
Affiliation(s)
- Sarah Kelliher
- School of Medicine, University College Dublin, Dublin, Ireland
- Stanford University School of Medicine, Stanford University, Stanford, CA, USA
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, Ireland
- UCD Conway SPHERE Research Group, University College Dublin, Dublin, Ireland
| | - Sara Gamba
- Department of Immunohematology and Transfusion Medicine, Hospital Papa Giovanni XXIII, Bergamo, Italy
| | - Luisa Weiss
- UCD Conway SPHERE Research Group, University College Dublin, Dublin, Ireland
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
| | - Zhu Shen
- Stanford University School of Medicine, Stanford University, Stanford, CA, USA
| | - Marina Marchetti
- Department of Immunohematology and Transfusion Medicine, Hospital Papa Giovanni XXIII, Bergamo, Italy
| | - Francesca Schieppati
- Department of Immunohematology and Transfusion Medicine, Hospital Papa Giovanni XXIII, Bergamo, Italy
| | - Caitriona Scaife
- UCD Conway Institute for Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
| | - Stephen Madden
- Data Science Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Kathleen Bennett
- School of Population Health, RCSI University of Medicine and Health Sciences, Dublin, Ireland
| | - Anne Fortune
- School of Medicine, University College Dublin, Dublin, Ireland
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Su Maung
- School of Medicine, University College Dublin, Dublin, Ireland
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Michael Fay
- School of Medicine, University College Dublin, Dublin, Ireland
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, Ireland
| | - Fionnuala Ní Áinle
- School of Medicine, University College Dublin, Dublin, Ireland
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, Ireland
- UCD Conway SPHERE Research Group, University College Dublin, Dublin, Ireland
- School of Medicine, Royal College of Surgeons in Ireland
| | - Patricia Maguire
- UCD Conway SPHERE Research Group, University College Dublin, Dublin, Ireland
- School of Biomolecular and Biomedical Science, University College Dublin, Dublin, Ireland
- UCD Institute for Discovery, University College Dublin, Dublin, Ireland
| | - Anna Falanga
- Department of Immunohematology and Transfusion Medicine, Hospital Papa Giovanni XXIII, Bergamo, Italy
- University of Milano-Bicocca, Department of Medicine and Surgery, Monza, Italy
| | - Barry Kevane
- School of Medicine, University College Dublin, Dublin, Ireland
- Department of Haematology, Mater Misericordiae University Hospital, Dublin, Ireland
- UCD Conway SPHERE Research Group, University College Dublin, Dublin, Ireland
| | - Anandi Krishnan
- Stanford University School of Medicine, Stanford University, Stanford, CA, USA
- Rutgers University, Piscataway, NJ
- Stanford Cancer Institute, Stanford, CA, USA
| |
Collapse
|
5
|
Noda K, Lu SL, Chen S, Tokuda K, Li Y, Hao F, Wada Y, Sun-Wada GH, Murakami S, Fukuda M, Itoh T, Noda T. Characterization of Rab32- and Rab38-positive lysosome-related organelles in osteoclasts and macrophages. J Biol Chem 2023; 299:105191. [PMID: 37625588 PMCID: PMC10518718 DOI: 10.1016/j.jbc.2023.105191] [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: 06/20/2022] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Both the biogenesis and functions of osteoclasts and macrophages involves dynamic membrane traffic. We screened transcript levels for Rab family small GTPases related to osteoclasts and identified Rab38. Rab38 expression is upregulated during osteoclast differentiation and maturation. In osteoclasts, both Rab38 and its paralog, Rab32, colocalize to lysosome-related organelles (LROs). In macrophages, Rab32 is also found in LROs. LROs are part of the endocytic pathway but are distinct from lysosomes. After receptor activator of NF-κB ligand stimulation, LROs contain cathepsin K and tartrate-resistant acid phosphatase inside and help both proteins to accumulate around bone resorption pits. After osteoclast maturation, these enzymes are hardly found within LROs. In macrophages derived from Rab32 and Rab38 double knockout mice, both acidification and V-ATPase a3 localization were severely compromised. Both the double knockout macrophage and bafilomycin-treated wildtype macrophage show an increase in Lamp1-positive organelles, implying that biogenesis of lysosomes and LROs are related. These results indicate that Rab32 and Rab38 both play a crucial role in LRO biogenesis in macrophages and in osteoclasts.
Collapse
Affiliation(s)
- Kazuya Noda
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan; Department of Periodontology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Shiou-Ling Lu
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Siyu Chen
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Kanako Tokuda
- Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yangjie Li
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Feike Hao
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Yoh Wada
- Department of Biological Sciences, Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan; Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan
| | - Ge-Hong Sun-Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyoto, Japan
| | - Shinya Murakami
- Department of Periodontology, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Mitsunori Fukuda
- Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Miyagi, Japan
| | - Takashi Itoh
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan
| | - Takeshi Noda
- Department of Oral Cell Biology, Center for Frontier Oral Science, Graduate School of Dentistry, Osaka University, Osaka, Japan; Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan; Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan.
| |
Collapse
|
6
|
Unapanta A, Shavarebi F, Porath J, Shen Y, Balen C, Nguyen A, Tseng J, Leong WS, Liu M, Lis P, Di Pietro SM, Hiniker A. Endogenous Rab38 regulates LRRK2's membrane recruitment and substrate Rab phosphorylation in melanocytes. J Biol Chem 2023; 299:105192. [PMID: 37625589 PMCID: PMC10551901 DOI: 10.1016/j.jbc.2023.105192] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Point mutations in leucine-rich repeat kinase 2 (LRRK2) cause Parkinson's disease and augment LRRK2's kinase activity. However, cellular pathways that endogenously enhance LRRK2 kinase function have not been identified. While overexpressed Rab29 draws LRRK2 to Golgi membranes to increase LRRK2 kinase activity, there is little evidence that endogenous Rab29 performs this function under physiological conditions. Here, we identify Rab38 as a novel physiologic regulator of LRRK2 in melanocytes. In mouse melanocytes, which express high levels of Rab38, Rab32, and Rab29, knockdown (or CRISPR knockout) of Rab38, but not Rab32 or Rab29, decreases phosphorylation of multiple LRRK2 substrates, including Rab10 and Rab12, by both endogenous LRRK2 and exogenous Parkinson's disease-mutant LRRK2. In B16-F10 mouse melanoma cells, Rab38 drives LRRK2 membrane association and overexpressed kinase-active LRRK2 shows striking pericentriolar recruitment, which is dependent on the presence of endogenous Rab38 but not Rab32 or Rab29. Consistently, knockdown or mutation of BLOC-3, the guanine nucleotide exchange factor for Rab38 and Rab32, inhibits Rab38's regulation of LRRK2. Deletion or mutation of LRRK2's Rab38-binding site in the N-terminal armadillo domain decreases LRRK2 membrane association, pericentriolar recruitment, and ability to phosphorylate Rab10. In sum, our data identify Rab38 as a physiologic regulator of LRRK2 function and lend support to a model in which LRRK2 plays a central role in Rab GTPase coordination of vesicular trafficking.
Collapse
Affiliation(s)
- Alexandra Unapanta
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Farbod Shavarebi
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Jacob Porath
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Yiyi Shen
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Carson Balen
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Albert Nguyen
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Josh Tseng
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Weng Si Leong
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Michelle Liu
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Pawel Lis
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee, Scotland, UK
| | - Santiago M Di Pietro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Annie Hiniker
- Department of Pathology, University of California San Diego, San Diego, California, USA.
| |
Collapse
|
7
|
Beyers WC, Detry AM, Di Pietro SM. OCA7 is a melanosome membrane protein that defines pigmentation by regulating early stages of melanosome biogenesis. J Biol Chem 2022; 298:102669. [PMID: 36334630 DOI: 10.1016/j.jbc.2022.102669] [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: 06/15/2022] [Revised: 10/21/2022] [Accepted: 10/24/2022] [Indexed: 11/11/2022] Open
Abstract
Mutations in C10orf11 (oculocutaneous albinism type 7 [OCA7]) cause OCA, a disorder that presents with hypopigmentation in skin, eyes, and hair. The OCA7 pathophysiology is unknown, and there is virtually no information on the OCA7 protein and its cellular function. Here, we discover that OCA7 localizes to the limiting membrane of melanosomes, the specialized pigment cell organelles where melanin is synthesized. We demonstrate that OCA7 is recruited through interaction with a canonical effector-binding surface of melanosome proteins Rab32 and Rab38. Using newly generated OCA7-KO MNT1 cells, we show OCA7 regulates overall melanin levels in a melanocyte autonomous manner by controlling melanosome maturation. Importantly, we found that OCA7 regulates premelanosome protein (PMEL) processing, impacting fibrillation and the striations that define transition from melanosome stage I to stage II. Furthermore, the melanosome lumen of OCA7-KO cells displays lower pH than control cells. Together, our results reveal that OCA7 regulates pigmentation through two well-established determinants of melanosome biogenesis and function, PMEL processing, and organelle pH.
Collapse
Affiliation(s)
- Wyatt C Beyers
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Anna M Detry
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA
| | - Santiago M Di Pietro
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, USA.
| |
Collapse
|
8
|
Rab32/38-Dependent and -Independent Transport of Tyrosinase to Melanosomes in B16-F1 Melanoma Cells. Int J Mol Sci 2022; 23:ijms232214144. [PMID: 36430618 PMCID: PMC9695596 DOI: 10.3390/ijms232214144] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 11/11/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022] Open
Abstract
B16-F1 melanoma cells have often been used as a model to investigate melanogenesis, but the evidence that melanosome biogenesis and transport occur by the same mechanisms in normal melanocytes and B16-F1 cells is insufficient. In this study, we established knockout B16-F1 cells for each of several key factors in melanogenesis, i.e., tyrosinase (Tyr), Hps4, Rab27A, and Rab32·Rab38 (Rab32/38), and then compared their phenotypes with the phenotypes of corresponding mutant mouse melanocyte cell lines, i.e., melan-c, melan-le, melan-ash, and Rab32-deficient melan-cht cells, respectively. The results showed that Tyr and Rab27A are also indispensable for melanin synthesis and peripheral melanosome distribution, respectively, in B16-F1 cells, but that Hps4 or its downstream targets Rab32/38 are not essential for Tyr transport in B16-F1 cells, suggesting the existence of a Rab32/38-independent Tyr transport mechanism in B16-F1 cells. We then performed comprehensive knockdown screening of Rab small GTPases and identified Rab10 and Rab24, previously uncharacterized Rabs in melanocytes, as being involved in Tyr transport under Rab32/38-null conditions. Our findings indicate a difference between the Tyr transport mechanism in melanocytes and B16-F1 cells in terms of Rab32/38-dependency and a limitation in regard to using melanoma cells as a model for melanocytes, especially when investigating the mechanism of endosomal Tyr transport.
Collapse
|
9
|
Mitochondrial a Kinase Anchor Proteins in Cardiovascular Health and Disease: A Review Article on Behalf of the Working Group on Cellular and Molecular Biology of the Heart of the Italian Society of Cardiology. Int J Mol Sci 2022; 23:ijms23147691. [PMID: 35887048 PMCID: PMC9322728 DOI: 10.3390/ijms23147691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 12/10/2022] Open
Abstract
Second messenger cyclic adenosine monophosphate (cAMP) has been found to regulate multiple mitochondrial functions, including respiration, dynamics, reactive oxygen species production, cell survival and death through the activation of cAMP-dependent protein kinase A (PKA) and other effectors. Several members of the large family of A kinase anchor proteins (AKAPs) have been previously shown to locally amplify cAMP/PKA signaling to mitochondria, promoting the assembly of signalosomes, regulating multiple cardiac functions under both physiological and pathological conditions. In this review, we will discuss roles and regulation of major mitochondria-targeted AKAPs, along with opportunities and challenges to modulate their functions for translational purposes in the cardiovascular system.
Collapse
|
10
|
Omata Y, Okada H, Uebe S, Izawa N, Ekici AB, Sarter K, Saito T, Schett G, Tanaka S, Zaiss MM. Interspecies Single-Cell RNA-Seq Analysis Reveals the Novel Trajectory of Osteoclast Differentiation and Therapeutic Targets. JBMR Plus 2022; 6:e10631. [PMID: 35866155 PMCID: PMC9289986 DOI: 10.1002/jbm4.10631] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/28/2022] [Accepted: 04/13/2022] [Indexed: 11/08/2022] Open
Abstract
Bone turnover is finely tuned by cells in the bone milieu, including osteoblasts, osteoclasts, and osteocytes. Osteoclasts are multinucleated giant cells with a bone-resorbing function that play a critical role in regulating skeletal homeostasis. Osteoclast differentiation is characterized by dramatic changes in morphology and gene expression following receptor activator of nuclear factor-kappa-Β ligand (RANKL) stimulation. We performed single-cell RNA-sequencing analyses of human and murine osteoclast-lineage cells (OLCs) and found that OLCs in the mitotic phase do not differentiate into mature osteoclasts. We also identified a guanosine triphosphatase (GTPase) family member, RAB38, as a highly expressed molecule in both human and murine osteoclast clusters; RAB38 gene expression is associated with dynamic changes in histone modification and transcriptional regulation. Silencing Rab38 expression by using short hairpin RNA (shRNA) inhibited osteoclast differentiation and maturation. In summary, we established an integrated fate map of human and murine osteoclastogenesis; this will help identify therapeutic targets in bone diseases. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Yasunori Omata
- Department of Internal Medicine 3, Rheumatology and ImmunologyFriedrich‐Alexander‐University Erlangen‐Nürnberg (FAU) and Universitätsklinikum ErlangenErlangenGermany
- Department of Orthopaedic Surgery, Faculty of MedicineThe University of TokyoTokyoJapan
- Bone and Cartilage Regenerative Medicine, Graduate School of MedicineThe University of TokyoTokyoJapan
| | - Hiroyuki Okada
- Department of Orthopaedic Surgery, Faculty of MedicineThe University of TokyoTokyoJapan
- Center for Disease Biology and Integrative MedicineThe University of TokyoTokyoJapan
| | - Steffen Uebe
- Institute of Human GeneticsUniversity of Hospital, Friedrich‐Alexander‐University Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - Naohiro Izawa
- Department of Orthopaedic Surgery, Faculty of MedicineThe University of TokyoTokyoJapan
- Department of Orthopaedic SurgerySaitama Medical UniversitySaitamaJapan
| | - Arif B. Ekici
- Institute of Human GeneticsUniversity of Hospital, Friedrich‐Alexander‐University Erlangen‐Nürnberg (FAU)ErlangenGermany
| | - Kerstin Sarter
- Department of Internal Medicine 3, Rheumatology and ImmunologyFriedrich‐Alexander‐University Erlangen‐Nürnberg (FAU) and Universitätsklinikum ErlangenErlangenGermany
| | - Taku Saito
- Department of Orthopaedic Surgery, Faculty of MedicineThe University of TokyoTokyoJapan
| | - Georg Schett
- Department of Internal Medicine 3, Rheumatology and ImmunologyFriedrich‐Alexander‐University Erlangen‐Nürnberg (FAU) and Universitätsklinikum ErlangenErlangenGermany
| | - Sakae Tanaka
- Department of Orthopaedic Surgery, Faculty of MedicineThe University of TokyoTokyoJapan
| | - Mario M. Zaiss
- Department of Internal Medicine 3, Rheumatology and ImmunologyFriedrich‐Alexander‐University Erlangen‐Nürnberg (FAU) and Universitätsklinikum ErlangenErlangenGermany
| |
Collapse
|
11
|
Caux M, Mansour R, Xuereb JM, Chicanne G, Viaud J, Vauclard A, Boal F, Payrastre B, Tronchère H, Severin S. PIKfyve-Dependent Phosphoinositide Dynamics in Megakaryocyte/Platelet Granule Integrity and Platelet Functions. Arterioscler Thromb Vasc Biol 2022; 42:987-1004. [PMID: 35708031 DOI: 10.1161/atvbaha.122.317559] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Secretory granules are key elements for platelet functions. Their biogenesis and integrity are regulated by fine-tuned mechanisms that need to be fully characterized. Here, we investigated the role of the phosphoinositide 5-kinase PIKfyve and its lipid products, PtdIns5P (phosphatidylinositol 5 monophosphate) and PtdIns(3,5)P2 (phosphatidylinositol (3,5) bisphosphate) in granule homeostasis in megakaryocytes and platelets. METHODS For that, we invalidated PIKfyve by pharmacological inhibition or gene silencing in megakaryocytic cell models (human MEG-01 cell line, human imMKCLs, mouse primary megakaryocytes) and in human platelets. RESULTS We unveiled that PIKfyve expression and its lipid product levels increased with megakaryocytic maturation. In megakaryocytes, PtdIns5P and PtdIns(3,5)P2 were found in alpha and dense granule membranes with higher levels in dense granules. Pharmacological inhibition or knock-down of PIKfyve in megakaryocytes decreased PtdIns5P and PtdIns(3,5)P2 synthesis and induced a vacuolar phenotype with a loss of alpha and dense granule identity. Permeant PtdIns5P and PtdIns(3,5)P2 and the cation channel TRPML1 (transient receptor potential mucolipins) and TPC2 activation were able to accelerate alpha and dense granule integrity recovery following release of PIKfyve pharmacological inhibition. In platelets, PIKfyve inhibition specifically impaired the integrity of dense granules culminating in defects in their secretion, platelet aggregation, and thrombus formation. CONCLUSIONS These data demonstrated that PIKfyve and its lipid products PtdIns5P and PtdIns(3,5)P2 control granule integrity both in megakaryocytes and platelets.
Collapse
Affiliation(s)
- Manuella Caux
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Rana Mansour
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Jean-Marie Xuereb
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Gaëtan Chicanne
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Julien Viaud
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Alicia Vauclard
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Frédéric Boal
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Bernard Payrastre
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.).,CHU de Toulouse, Laboratoire d'Hématologie, Toulouse, France (B.P.)
| | - Hélène Tronchère
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| | - Sonia Severin
- INSERM U1297, I2MC and Université Paul Sabatier, Toulouse, France (M.C., R.M., J.-M.X., G.C., J.V., A.V., F.B., B.P., H.T., S.S.)
| |
Collapse
|
12
|
Li W, Hao CJ, Hao ZH, Ma J, Wang QC, Yuan YF, Gong JJ, Chen YY, Yu JY, Wei AH. New insights into the pathogenesis of Hermansky-Pudlak syndrome. Pigment Cell Melanoma Res 2022; 35:290-302. [PMID: 35129281 DOI: 10.1111/pcmr.13030] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/02/2022] [Accepted: 02/03/2022] [Indexed: 12/14/2022]
Abstract
Hermansky-Pudlak syndrome (HPS) is characterized by defects of multiple tissue-specific lysosome-related organelles (LROs), typically manifesting with oculocutaneous albinism or ocular albinism, bleeding tendency, and in some cases with pulmonary fibrosis, inflammatory bowel disease or immunodeficiency, neuropsychological disorders. Eleven HPS subtypes in humans and at least 15 subtypes in mice have been molecularly identified. Current understanding of the underlying mechanisms of HPS is focusing on the defective biogenesis of LROs. Compelling evidences have shown that HPS protein-associated complexes (HPACs) function in cargo transport, cargo recycling, and cargo removal to maintain LRO homeostasis. Further investigation on the molecular and cellular mechanism of LRO biogenesis and secretion will be helpful for better understanding of its pathogenesis and for the precise intervention of HPS.
Collapse
Affiliation(s)
- Wei Li
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Chan-Juan Hao
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Zhen-Hua Hao
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Jing Ma
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Qiao-Chu Wang
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Ye-Feng Yuan
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Juan-Juan Gong
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Yuan-Ying Chen
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Jia-Ying Yu
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute, Beijing Children's Hospital, Capital Medical University, Center of Rare Diseases, National Center for Children's Health, Beijing, China.,MOE Key Laboratory of Major Diseases in Children, Capital Medical University, Beijing, China
| | - Ai-Hua Wei
- Department of Dermatology, Tongren Hospital, Capital Medical University, Beijing, China
| |
Collapse
|
13
|
Yuan Y, Liu T, Huang X, Chen Y, Zhang W, Li T, Yang L, Chen Q, Wang Y, Wei A, Li W. A zinc transporter, transmembrane protein 163, is critical for the biogenesis of platelet dense granules. Blood 2021; 137:1804-1817. [PMID: 33513603 PMCID: PMC8020268 DOI: 10.1182/blood.2020007389] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 01/03/2021] [Indexed: 11/20/2022] Open
Abstract
Lysosome-related organelles (LROs) are a category of secretory organelles enriched with ions such as calcium, which are maintained by ion transporters or channels. Homeostasis of these ions is important for LRO biogenesis and secretion. Hermansky-Pudlak syndrome (HPS) is a recessive disorder with defects in multiple LROs, typically platelet dense granules (DGs) and melanosomes. However, the underlying mechanism of DG deficiency is largely unknown. Using quantitative proteomics, we identified a previously unreported platelet zinc transporter, transmembrane protein 163 (TMEM163), which was significantly reduced in BLOC-1 (Dtnbp1sdy and Pldnpa)-, BLOC-2 (Hps6ru)-, or AP-3 (Ap3b1pe)-deficient mice and HPS patients (HPS2, HPS3, HPS5, HPS6, or HPS9). We observed similar platelet DG defects and higher intracellular zinc accumulation in platelets of mice deficient in either TMEM163 or dysbindin (a BLOC-1 subunit). In addition, we discovered that BLOC-1 was required for the trafficking of TMEM163 to perinuclear DG and late endosome marker-positive compartments (likely DG precursors) in MEG-01 cells. Our results suggest that TMEM163 is critical for DG biogenesis and that BLOC-1 is required for the trafficking of TMEM163 to putative DG precursors. These new findings suggest that loss of TMEM163 function results in disruption of intracellular zinc homeostasis and provide insights into the pathogenesis of HPS or platelet storage pool deficiency.
Collapse
Affiliation(s)
- Yefeng Yuan
- Beijing Key Laboratory for Genetics of Birth Defects/Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center/National Center for Children's Health, and Beijing Children's Hospital/Capital Medical University, Beijing, China
- University of Chinese Academy of Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Teng Liu
- Department of Dermatology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
- Shunyi Women and Children's Hospital of Beijing Children's Hospital, Beijing, China
| | - Xiahe Huang
- University of Chinese Academy of Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yuanying Chen
- Beijing Key Laboratory for Genetics of Birth Defects/Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center/National Center for Children's Health, and Beijing Children's Hospital/Capital Medical University, Beijing, China
| | - Weilin Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; and
| | - Ting Li
- University of Chinese Academy of Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Lin Yang
- University of Chinese Academy of Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Quan Chen
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; and
- Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin, China
| | - Yingchun Wang
- University of Chinese Academy of Sciences, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Aihua Wei
- Department of Dermatology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Wei Li
- Beijing Key Laboratory for Genetics of Birth Defects/Beijing Pediatric Research Institute, MOE Key Laboratory of Major Diseases in Children, Genetics and Birth Defects Control Center/National Center for Children's Health, and Beijing Children's Hospital/Capital Medical University, Beijing, China
- Shunyi Women and Children's Hospital of Beijing Children's Hospital, Beijing, China
| |
Collapse
|
14
|
Platelet life without TMEM163: no dense granules. Blood 2021; 137:1708-1709. [PMID: 33792677 DOI: 10.1182/blood.2021010691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
15
|
McGrath E, Waschbüsch D, Baker BM, Khan AR. LRRK2 binds to the Rab32 subfamily in a GTP-dependent manner via its armadillo domain. Small GTPases 2021; 12:133-146. [PMID: 31552791 PMCID: PMC7849779 DOI: 10.1080/21541248.2019.1666623] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/26/2019] [Accepted: 09/02/2019] [Indexed: 12/31/2022] Open
Abstract
LRRK2 is a multi-domain Ser/Thr kinase that is associated with inherited and sporadic cases of Parkinson's disease. Many mutations linked to disease are associated within a central ROC-COR regulatory region and the subsequent kinase domain, leading to enhanced catalytic activity. The N-terminus of human LRRK2 consists of armadillo repeat motifs (ARMs) followed by ankyrin repeats (ANKs). Recently, Rab GTPases have emerged as key players in LRRK2 function, both as substrates of the kinase, and as regulators of the catalytic activity. Rabs recruit effector proteins via their GTP-dependent switch 1 and 2 regions to distinct sub-cellular compartments to regulate membrane trafficking. LRRK2 phosphorylates Rab8, Rab10 and Rab12 in switch 2, and this activity is regulated via interactions with Rab29. Furthermore, the related Rab32-subfamily GTPases, Rab32 and Rab38, have also been shown to interact with LRRK2. Here, we have mapped the interactions of the Rab32-subfamily to the ARM domain of LRRK2. The complexes are dependent on the GTP state of the Rabs in vitro, implying that LRRK2 may be an effector of the Rab32-subfamily of small GTPases. X-ray crystal structures of the Rab32-family GTPases and subsequent mutational studies reveal that a positively charged residue in switch 1 is critical for binding of Rab32/38 to LRRK2. Homology modelling and mutational analyses of the ARM domain point to a patch of negatively charged residues that contribute to complex formation. These structural and biochemical studies provide a framework for understanding the molecular basis for Rab regulation of LRRK2 and its role in Parkinson's disease.
Collapse
Affiliation(s)
- Emma McGrath
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
| | - Dieter Waschbüsch
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| | - Brian M. Baker
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN
| | - Amir R. Khan
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland
| |
Collapse
|
16
|
Fukuda M. Rab GTPases: Key players in melanosome biogenesis, transport, and transfer. Pigment Cell Melanoma Res 2020; 34:222-235. [PMID: 32997883 DOI: 10.1111/pcmr.12931] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/23/2020] [Indexed: 12/12/2022]
Abstract
Melanosomes are specialized intracellular organelles that produce and store melanin pigments in melanocytes, which are present in several mammalian tissues and organs, including the skin, hair, and eyes. Melanosomes form and mature stepwise (stages I-IV) in melanocytes and then are transported toward the plasma membrane along the cytoskeleton. They are subsequently transferred to neighboring keratinocytes by a largely unknown mechanism, and incorporated melanosomes are transported to the perinuclear region of the keratinocytes where they form melanin caps. Melanocytes also extend several dendrites that facilitate the efficient transfer of the melanosomes to the keratinocytes. Since the melanosome biogenesis, transport, and transfer steps require multiple membrane trafficking processes, Rab GTPases that are conserved key regulators of membrane traffic in all eukaryotes are crucial for skin and hair pigmentation. Dysfunctions of two Rab isoforms, Rab27A and Rab38, are known to cause a hypopigmentation phenotype in human type 2 Griscelli syndrome patients and in chocolate mice (related to Hermansky-Pudlak syndrome), respectively. In this review article, I review the literature on the functions of each Rab isoform and its upstream and downstream regulators in mammalian melanocytes and keratinocytes.
Collapse
Affiliation(s)
- Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, Japan
| |
Collapse
|
17
|
Tomaiuolo M, Litvinov RI, Weisel JW, Stalker TJ. Use of electron microscopy to study platelets and thrombi. Platelets 2020; 31:580-588. [PMID: 32423268 PMCID: PMC7332414 DOI: 10.1080/09537104.2020.1763939] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/22/2020] [Accepted: 04/27/2020] [Indexed: 01/23/2023]
Abstract
Electron microscopy has been a valuable tool for the study of platelet biology and thrombosis for more than 70 years. Early studies using conventional transmission and scanning electron microscopy (EM) provided a foundation for our initial understanding of platelet structure and how it changes upon platelet activation. EM approaches have since been utilized to study platelets and thrombi in the context of basic, translational and clinical research, and they are instrumental in the diagnosis of multiple platelet function disorders. In this brief review, we provide a sampling of the many contributions EM based studies have made to the field, including both historical highlights and contemporary applications. We will also discuss exciting new imaging modalities based on EM and their utility for the study of platelets, hemostasis and thrombosis into the future.
Collapse
Affiliation(s)
| | - Rustem I. Litvinov
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | - John W. Weisel
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, USA
| | | |
Collapse
|
18
|
Homma Y, Hiragi S, Fukuda M. Rab family of small GTPases: an updated view on their regulation and functions. FEBS J 2020; 288:36-55. [PMID: 32542850 PMCID: PMC7818423 DOI: 10.1111/febs.15453] [Citation(s) in RCA: 206] [Impact Index Per Article: 51.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 05/27/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022]
Abstract
The Rab family of small GTPases regulates intracellular membrane trafficking by orchestrating the biogenesis, transport, tethering, and fusion of membrane‐bound organelles and vesicles. Like other small GTPases, Rabs cycle between two states, an active (GTP‐loaded) state and an inactive (GDP‐loaded) state, and their cycling is catalyzed by guanine nucleotide exchange factors (GEFs) and GTPase‐activating proteins (GAPs). Because an active form of each Rab localizes on a specific organelle (or vesicle) and recruits various effector proteins to facilitate each step of membrane trafficking, knowing when and where Rabs are activated and what effectors Rabs recruit is crucial to understand their functions. Since the discovery of Rabs, they have been regarded as one of the central hubs for membrane trafficking, and numerous biochemical and genetic studies have revealed the mechanisms of Rab functions in recent years. The results of these studies have included the identification and characterization of novel GEFs, GAPs, and effectors, as well as post‐translational modifications, for example, phosphorylation, of Rabs. Rab functions beyond the simple effector‐recruiting model are also emerging. Furthermore, the recently developed CRISPR/Cas technology has enabled acceleration of knockout analyses in both animals and cultured cells and revealed previously unknown physiological roles of many Rabs. In this review article, we provide the most up‐to‐date and comprehensive lists of GEFs, GAPs, effectors, and knockout phenotypes of mammalian Rabs and discuss recent findings in regard to their regulation and functions.
Collapse
Affiliation(s)
- Yuta Homma
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Shu Hiragi
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| |
Collapse
|
19
|
Karampini E, Bierings R, Voorberg J. Orchestration of Primary Hemostasis by Platelet and Endothelial Lysosome-Related Organelles. Arterioscler Thromb Vasc Biol 2020; 40:1441-1453. [PMID: 32375545 DOI: 10.1161/atvbaha.120.314245] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Megakaryocyte-derived platelets and endothelial cells store their hemostatic cargo in α- and δ-granules and Weibel-Palade bodies, respectively. These storage granules belong to the lysosome-related organelles (LROs), a heterogeneous group of organelles that are rapidly released following agonist-induced triggering of intracellular signaling pathways. Following vascular injury, endothelial Weibel-Palade bodies release their content into the vascular lumen and promote the formation of long VWF (von Willebrand factor) strings that form an adhesive platform for platelets. Binding to VWF strings as well as exposed subendothelial collagen activates platelets resulting in the release of α- and δ-granules, which are crucial events in formation of a primary hemostatic plug. Biogenesis and secretion of these LROs are pivotal for the maintenance of proper hemostasis. Several bleeding disorders have been linked to abnormal generation of LROs in megakaryocytes and endothelial cells. Recent reviews have emphasized common pathways in the biogenesis and biological properties of LROs, focusing mainly on melanosomes. Despite many similarities, LROs in platelet and endothelial cells clearly possess distinct properties that allow them to provide a highly coordinated and synergistic contribution to primary hemostasis by sequentially releasing hemostatic cargo. In this brief review, we discuss in depth the known regulators of α- and δ-granules in megakaryocytes/platelets and Weibel-Palade bodies in endothelial cells, starting from transcription factors that have been associated with granule formation to protein complexes that promote granule maturation. In addition, we provide a detailed view on the interplay between platelet and endothelial LROs in controlling hemostasis as well as their dysfunction in LRO related bleeding disorders.
Collapse
Affiliation(s)
- Ellie Karampini
- From the Department of Molecular and Cellular Hemostasis, Sanquin Research and Landsteiner Laboratory (E.K., R.B., J.V.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands
| | - Ruben Bierings
- From the Department of Molecular and Cellular Hemostasis, Sanquin Research and Landsteiner Laboratory (E.K., R.B., J.V.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands.,Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands (R.B.)
| | - Jan Voorberg
- From the Department of Molecular and Cellular Hemostasis, Sanquin Research and Landsteiner Laboratory (E.K., R.B., J.V.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands.,Experimental Vascular Medicine (J.V.), Amsterdam University Medical Center, University of Amsterdam, the Netherlands
| |
Collapse
|