scholarly journals LRRK2-phosphorylated Rab10 sequesters Myosin Va with RILPL2 during ciliogenesis blockade

2021 ◽  
Vol 4 (5) ◽  
pp. e202101050
Author(s):  
Herschel S Dhekne ◽  
Izumi Yanatori ◽  
Edmundo G Vides ◽  
Yuriko Sobu ◽  
Federico Diez ◽  
...  
Keyword(s):  
Dependent Manner ◽  
Rab Gtpases ◽  
Tail Domain ◽  
Over Expression ◽  
Activating Mutations ◽  
High Affinity Binding Site ◽  
Mother Centriole ◽  
Myosin Va ◽  
Lrrk2 Kinase ◽  
Rab Effector

Activating mutations in LRRK2 kinase causes Parkinson’s disease. Pathogenic LRRK2 phosphorylates a subset of Rab GTPases and blocks ciliogenesis. Thus, defining novel phospho-Rab interacting partners is critical to our understanding of the molecular basis of LRRK2 pathogenesis. RILPL2 binds with strong preference to LRRK2-phosphorylated Rab8A and Rab10. RILPL2 is a binding partner of the motor protein and Rab effector, Myosin Va. We show here that the globular tail domain of Myosin Va also contains a high affinity binding site for LRRK2-phosphorylated Rab10. In the presence of pathogenic LRRK2, RILPL2 and MyoVa relocalize to the peri-centriolar region in a phosphoRab10-dependent manner. PhosphoRab10 retains Myosin Va over pericentriolar membranes as determined by fluorescence loss in photobleaching microscopy. Without pathogenic LRRK2, RILPL2 is not essential for ciliogenesis but RILPL2 over-expression blocks ciliogenesis in RPE cells independent of tau tubulin kinase recruitment to the mother centriole. These experiments show that LRRK2 generated-phosphoRab10 dramatically redistributes a significant fraction of Myosin Va and RILPL2 to the mother centriole in a manner that likely interferes with Myosin Va’s role in ciliogenesis.

scholarly journals LRRK2-phosphorylated Rab10 sequesters Myosin Va with RILPL2 during ciliogenesis blockade

2020 ◽  
Author(s):  
Izumi Yanatori ◽  
Herschel S. Dhekne ◽  
Edmundo G. Vides ◽  
Yuriko Sobu ◽  
Federico Diez ◽  
...  
Keyword(s):  
Dependent Manner ◽  
Rab Gtpases ◽  
Tail Domain ◽  
Binding Partner ◽  
Activating Mutations ◽  
High Affinity Binding Site ◽  
Mother Centriole ◽  
Myosin Va ◽  
Lrrk2 Kinase ◽  
Rab Effector

AbstractActivating mutations in LRRK2 kinase cause Parkinson’s disease. Pathogenic LRRK2 phosphorylates a subset of Rab GTPases and blocks ciliogenesis. Thus, defining novel phospho-Rab interacting partners is critical to our understanding of the molecular basis of LRRK2 pathogenesis. RILPL2 binds with strong preference to LRRK2-phosphorylated Rab8A and Rab10. RILPL2 is a binding partner of the motor protein and Rab effector, Myosin Va. We show here that the globular tail domain of Myosin Va also contains a high affinity binding site for LRRK2-phosphorylated Rab10, and certain tissue-specific Myosin Va isoforms strongly prefer to bind phosphorylated Rab10. In the presence of pathogenic LRRK2, RILPL2 relocalizes to the peri-centriolar region in a phosphoRab10- and Myosin Va-dependent manner. In the absence of phosphoRab10, expression of RILPL2 or depletion of Myosin Va increase centriolar RILPL2 levels, and either condition is sufficient to block ciliogenesis in RPE cells. These experiments show that LRRK2 generated phosphoRab10 dramatically redistributes Myosin Va-RILPL2 complexes to the mother centriole, which may sequester Myosin Va and RILPL2 in a manner that blocks their normal roles in ciliogenesis.

Rab27a enables myosin Va-dependent melanosome capture by recruiting the myosin to the organelle

2001 ◽  
Vol 114 (6) ◽  
pp. 1091-1100 ◽  
Author(s):  
X. Wu ◽  
K. Rao ◽  
M.B. Bowers ◽  
N.G. Copeland ◽  
N.A. Jenkins ◽  
...  
Keyword(s):  
Wild Type Mouse ◽  
Dendritic Morphology ◽  
Dependent Manner ◽  
Rab Gtpases ◽  
Tail Domain ◽  
Wild Type ◽  
Cooperative Process ◽  
Myosin Va ◽  
Dependent Transport ◽  
End Stage

The peripheral accumulation of melanosomes characteristic of wild-type mouse melanocytes is driven by a cooperative process involving long-range, bidirectional, microtubule-dependent movements coupled to capture and local movement in the actin-rich periphery by myosin Va, the product of the dilute locus. Genetic evidence suggests that Rab27a, the product of the ashen locus, functions with myosin Va in this process. Here we show that ashen melanocytes, like dilute melanocytes, exhibit normal dendritic morphology and melanosome biogenesis, an abnormal accumulation of end-stage melanosomes in the cell center, and rapid, bidirectional, microtubule-dependent melanosome movements between the cell center and the periphery. This phenotype suggests that ashen melanocytes, like dilute melanocytes, are defective in peripheral melanosome capture. Consistent with this, introduction into ashen melanocytes of cDNAs encoding wild-type and GTP-bound versions of Rab27a restores the peripheral accumulation of melanosomes in a microtubule-dependent manner. Conversely, introduction into wild-type melanocytes of the GDP-bound version of Rab27a generates an ashen/dilute phenotype. Rab27a colocalizes with end-stage melanosomes in wild-type cells, and is most concentrated in melanosome-rich dendritic tips, where it also colocalizes with myosin Va. Finally, neither endogenous myosin Va nor an expressed, GFP-tagged, myosin Va tail domain fusion protein colocalize with melanosomes in ashen melanocytes, in contrast to that seen previously in wild-type cells. These results argue that Rab27a serves to enable the myosinVa-dependent capture of melanosomes delivered to the periphery by bidirectional, microtubule-dependent transport, and that it does so by recruiting the myosin to the melanosome surface. We suggest that Rab27a, in its GTP-bound and melanosome-associated form, predominates in the periphery, and that it is this form that recruits the myosin, enabling capture. These results argue that Rab27a serves as a myosin Va ‘receptor’, and add to the growing evidence that Rab GTPases regulate vesicle motors as well as SNARE pairing.

scholarly journals LRRK2 causes centrosomal deficits via phosphorylated Rab10 and RILPL1 at centriolar subdistal appendages

2021 ◽  
Author(s):  
Antonio Jesús Lara Ordóňez ◽  
Belén Fernández ◽  
Rachel Fasiczka ◽  
Yahaira Naaldijk ◽  
Elena Fdez ◽  
...  
Keyword(s):  
Rab Gtpases ◽  
Rab Protein ◽  
Risk Variants ◽  
Mother Centriole ◽  
Dividing Cells ◽  
Intact Brain ◽  
Lrrk2 Kinase ◽  
Kinase Substrates ◽  
Lrrk2 Kinase Activity

The Parkinson′s disease-associated LRRK2 kinase phosphorylates multiple Rab GTPases including Rab8 and Rab10, which enhances their binding to RILPL1 and RILPL2. The nascent interaction between phospho-Rab10 and RILPL1 blocks ciliogenesis in vitro and in the intact brain, and interferes with the cohesion of duplicated centrosomes in dividing cells. We show here that various LRRK2 risk variants and all currently described regulators of the LRRK2 signaling pathway converge upon causing centrosomal cohesion deficits. The cohesion deficits do not require the presence of RILPL2 or of other LRRK2 kinase substrates including Rab12, Rab35 and Rab43. Rather, they depend on the RILPL1-mediated centrosomal accumulation of phosphorylated Rab10. RILPL1 localizes to the subdistal appendages of the mother centriole, followed by recruitment of the LRRK2-phosphorylated Rab protein to cause the centrosomal defects. These data reveal a common molecular pathway by which alterations in the LRRK2 kinase activity impact upon centrosome-related events.

scholarly journals Myosin Va mediates Rab8A-regulated GLUT4 vesicle exocytosis in insulin-stimulated muscle cells

2014 ◽  
Vol 25 (7) ◽  
pp. 1159-1170 ◽  
Author(s):  
Yi Sun ◽  
Tim T. Chiu ◽  
Kevin P. Foley ◽  
Philip J. Bilan ◽  
Amira Klip
Keyword(s):  
Muscle Cell ◽  
Fluorescent Protein ◽  
Motor Protein ◽  
Muscle Cells ◽  
Dependent Manner ◽  
Rab Gtpases ◽  
Vesicle Traffic ◽  
Myosin Va ◽  
Vesicle Exocytosis ◽  
Green Fluorescent

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.

The KLF6 Super Enhancer Modulates Cell Proliferation via MiR-1301 in Human Hepatoma Cells

MicroRNA ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 64-69 ◽  
Author(s):  
KumChol Ri ◽  
Chol Kim ◽  
CholJin Pak ◽  
PhyongChol Ri ◽  
HyonChol Om
Keyword(s):  
Cell Proliferation ◽  
Cellular Proliferation ◽  
Hepatoma Cells ◽  
Regulation Mechanism ◽  
Dependent Manner ◽  
Human Hepatoma ◽  
Human Hepatoma Cells ◽  
Over Expression ◽  
Super Enhancer ◽  
Engineering Changes

Background: Recent studies have attempted to elucidate the function of super enhancers by means of microRNAs. Although the functional outcomes of miR-1301 have become clearer, the pathways that regulate the expressions of miR-1301 remain unclear. Objective: The objective of this paper was to consider the pathway regulating expression of miR- 1301 and miR-1301 signaling pathways with the inhibition of cell proliferation. Methods: In this study, we prepared the cell clones that the KLF6 super enhancer was deleted by means of the CRISPR/Cas9 system-mediated genetic engineering. Changes in miR-1301 expression after the deletion of the KLF6 super enhancer were evaluated by RT-PCR analysis, and the signal pathway of miR-1301 with inhibition of the cell proliferation was examined using RNA interference technology. Results: The results showed that miR-1301 expression was significantly increased after the deletion of the KLF6 super enhancer. Over-expression of miR-1301 induced by deletion of the KLF6 super enhancer also regulated the expression of p21 and p53 in human hepatoma cells. functional modeling of findings using siRNA specific to miR-1301 showed that expression level changes had direct biological effects on cellular proliferation in Human hepatoma cells. Furthermore, cellular proliferation assay was shown to be directly associated with miR-1301 levels. Conclusion: As a result, it was demonstrated that the over-expression of miR-1301 induced by the disruption of the KLF6 super enhancer leads to a significant inhibition of proliferation in HepG2 cells. Moreover, it was demonstrated that the KLF6 super enhancer regulates the cell-proliferative effects which are mediated, at least in part, by the induction of p21and p53 in a p53-dependent manner. Our results provide the functional significance of miR-1301 in understanding the transcriptional regulation mechanism of the KLF6 super enhancer.

scholarly journals SVIP is a molecular determinant of lysosomal dynamic stability, neurodegeneration and lifespan

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alyssa E. Johnson ◽  
Brian O. Orr ◽  
Richard D. Fetter ◽  
Armen J. Moughamian ◽  
Logan A. Primeaux ◽  
...  
Keyword(s):  
Dynamic Stability ◽  
Muscle Wasting ◽  
Dependent Manner ◽  
Missense Mutations ◽  
Over Expression ◽  
System A ◽  
Molecular Determinant ◽  
Intracellular Organelles ◽  
Stress Dependent ◽  
Lateral Sclerosis

AbstractMissense mutations in Valosin-Containing Protein (VCP) are linked to diverse degenerative diseases including IBMPFD, amyotrophic lateral sclerosis (ALS), muscular dystrophy and Parkinson’s disease. Here, we characterize a VCP-binding co-factor (SVIP) that specifically recruits VCP to lysosomes. SVIP is essential for lysosomal dynamic stability and autophagosomal–lysosomal fusion. SVIP mutations cause muscle wasting and neuromuscular degeneration while muscle-specific SVIP over-expression increases lysosomal abundance and is sufficient to extend lifespan in a context, stress-dependent manner. We also establish multiple links between SVIP and VCP-dependent disease in our Drosophila model system. A biochemical screen identifies a disease-causing VCP mutation that prevents SVIP binding. Conversely, over-expression of an SVIP mutation that prevents VCP binding is deleterious. Finally, we identify a human SVIP mutation and confirm the pathogenicity of this mutation in our Drosophila model. We propose a model for VCP disease based on the differential, co-factor-dependent recruitment of VCP to intracellular organelles.

LukS-PV Induced HOXA9 Degradation in Acute Myeloid Leukemia Cells via Autophagy

2021 ◽  
Author(s):  
Ping Qiang ◽  
Chao Fang ◽  
Kaidi Song ◽  
Lan Shi ◽  
Yuanyuan Dai ◽  
...  
Keyword(s):  
Myeloid Leukemia ◽  
Leukemia Cells ◽  
Autophagic Flux ◽  
Dependent Manner ◽  
Prominent Feature ◽  
Concentration Dependent Manner ◽  
Over Expression ◽  
Autophagy Induction ◽  
Acute Myeloid Leukemia Cells ◽  
Acute Myeloid

Abstract Aberrant over-expression of HOXA9 is a prominent feature of AML driven by multiple oncogenes, thus therapeutic degradation of HOXA9 by autophagy may be an effective treatment strategy for AML. PVL is a pore forming cytotoxin secreted by Staphylococcus aureus, and it is composed of two subunits - LukS-PV and LukF-PV. Here, we show that LukS-PV can stimulate the conversion of LC3-I to LC3-II in AML cells in a concentration-dependent manner, and autophagic vacuoles can be found in LukS-PV-treated THP-1 cells. Furthermore, we find that an accumulation of LC3-positive structures in AML cells exposed to LukS-PV, indicating that an increased autophagic flux were formed. Therefore, LukS-PV induced autophagy of AML cells. We also demonstrated that LukS-PV could regulate the expression of HOXA9 at the protein level. HOXA9 molecules were detected in autophagosomes after LukS-PV treatment, indicating that autophagy induction accounted for the degradation of HOXA9.

scholarly journals Identification, characterization and cloning of myr 1, a mammalian myosin-I.

1993 ◽  
Vol 120 (6) ◽  
pp. 1393-1403 ◽  
Author(s):  
C Ruppert ◽  
R Kroschewski ◽  
M Bähler
Keyword(s):  
Amino Acid ◽  
Light Chain ◽  
Brush Border ◽  
Binding Sites ◽  
Neuronal Development ◽  
Amino Acid Sequences ◽  
Dependent Manner ◽  
Tail Domain ◽  
Myosin I ◽  
Splice Forms

We have identified, characterized and cloned a novel mammalian myosin-I motor-molecule, called myr 1 (myosin-I from rat). Myr 1 exists in three alternative splice forms: myr 1a, myr 1b, and myr 1c. These splice forms differ in their numbers of putative calmodulin/light chain binding sites. Myr 1a-c were selectively released by ATP, bound in a nucleotide-dependent manner to F-actin and exhibited amino acid sequences characteristic of myosin-I motor domains. In addition to the motor domain, they contained a regulatory domain with up to six putative calmodulin/light chain binding sites and a tail domain. The tail domain exhibited 47% amino acid sequence identity to the brush border myosin-I tail domain, demonstrating that myr 1 is related to the only other mammalian myosin-I motor molecule that has been characterized so far. In contrast to brush border myosin-I which is expressed in mature enterocytes, myr 1 splice forms were differentially expressed in all tested tissues. Therefore, myr 1 is the first mammalian myosin-I motor molecule with a widespread tissue distribution in neonatal and adult tissues. The myr 1a splice form was preferentially expressed in neuronal tissues. Its expression was developmentally regulated during rat forebrain ontogeny and subcellular fractionation revealed an enrichment in purified growth cone particles, data consistent with a role for myr 1a in neuronal development.

scholarly journals Functional Role of the Cytoplasmic Tail Domain of the Major Envelope Fusion Protein of Group II Baculoviruses

2006 ◽  
Vol 80 (22) ◽  
pp. 11226-11234 ◽  
Author(s):  
Gang Long ◽  
Xiaoyu Pan ◽  
Marcel Westenberg ◽  
Just M. Vlak
Keyword(s):  
Fusion Proteins ◽  
Functional Role ◽  
Cytoplasmic Tail ◽  
Viral Envelope ◽  
Repair System ◽  
Dependent Manner ◽  
Tail Domain ◽  
F Protein ◽  
Group Ii

ABSTRACT F proteins from baculovirus nucleopolyhedrovirus (NPV) group II members are the major budded virus (BV) viral envelope fusion proteins. They undergo furin-like proteolysis processing in order to be functional. F proteins from different baculovirus species have a long cytoplasmic tail domain (CTD), ranging from 48 (Spodoptera litura multicapsid NPV [MNPV]) to 78 (Adoxophyes honmai NPV) amino acid (aa) residues, with a nonassigned function. This CTD is much longer than the CTD of GP64-like envelope fusion proteins (7 aa), which appear to be nonessential for BV infectivity. Here we have investigated the functional role of the CTD of Helicoverpa armigera single-capsid NPV (HearNPV), a group II NPV. We combined a newly constructed HearNPV f-null bacmid knockout-repair system and an Autographa californica MNPV (AcMNPV) gp64-null bacmid knockout-pseudotype system with mutation and rescue experiments to study the functional role of the baculovirus F protein CTD. We show that except for the 16 C-terminal aa, the HearNPV F CTD is essential for virus spread from cell to cell. In addition, the CTD of HearNPV F is involved in BV production in a length-dependent manner and is essential for BV infectivity. The tyrosine residue Y658, located 16 aa from the C terminus, seems to be critical. However, HearNPV F without a CTD still rescues the infectivity of gp64-null AcMNPV BV, indicating that the CTD is not involved in processing and fusogenicity. Altogether, our results indicate that the F protein is essential for baculovirus BV infectivity and that the CTD is important for F protein incorporation into BV.

scholarly journals SUN-132 KLF5 Is a Poor Prognostic Marker and Therapeutic Target for Middle Eastern Papillary Thyroid Carcinoma

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Khawla S Al-Kuraya ◽  
Abdul K Siraj ◽  
Pratheeshkumar Poyil ◽  
Divya Padmaja ◽  
Sandeep Kumar Parvathareddy ◽  
...  
Keyword(s):  
Thyroid Cancer ◽  
Papillary Thyroid Carcinoma ◽  
Thyroid Carcinoma ◽  
Cell Lines ◽  
Therapeutic Target ◽  
Critical Role ◽  
Dependent Manner ◽  
Papillary Thyroid ◽  
Inhibition Of Proliferation ◽  
Over Expression

Abstract Thyroid cancer is the second most common malignancy among females in Saudi Arabia, with Papillary thyroid carcinoma (PTC) accounting for 80-90%. The Kruppel-like factor 5 (Klf5) is a transcription factor that play a critical role in cell transformation, proliferation and oncogenesis. Immunohistochemical analysis of KLF5 was performed in 1219 PTC cases. KLF5 over-expression was noted in 65.1% (793/1219) of PTCs, and was significantly associated with tall-cell variant (p <0.0001), extrathyroidal extension (p = 0.0003), lymph node metastasis (p < 0.0001) and stage IV tumors (p < 0.0001). Significant association was also noted with HIF-1α over-expression (p = 0.0492). Interestingly, KLF5 over-expressing tumors showed poor disease-free survival (p = 0.0066). Functional studies in PTC cell lines showed that KLF5 co-immunoprecipitated with HIF-1α. Knockdown of KLF5 decreased the expression of HIF-1α while KLF5 was not affected by HIF-1α inhibition, suggesting that KLF5 is a functional upstream of HIF-1α. Down-regulation of KLF5 using specific inhibitor, ML264 or siRNA inhibited cell invasion and migration. In addition, treatment of PTC cell lines with ML264 resulted in inhibition of proliferation and induction of apoptosis in a dose-dependent manner. Furthermore, silencing of KLF5 significantly decreased the self-renewal ability of spheroids generated from PTC cells. Our findings confer that KLF5 may be a potential therapeutic target for the treatment of papillary thyroid cancer.

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