Arfs and Arls: models for Arf family members in membrane traffic at the Golgi

RNA Interference Screening Identifies Novel Roles for RhoBTB1 and RhoBTB3 in Membrane Trafficking Events in Mammalian Cells

Cells ◽

10.3390/cells9051089 ◽

2020 ◽

Vol 9 (5) ◽

pp. 1089 ◽

Cited By ~ 1

Author(s):

Maeve Long ◽

Tilen Kranjc ◽

Margaritha M. Mysior ◽

Jeremy C. Simpson

Keyword(s):

Rna Interference ◽

Golgi Complex ◽

Membrane Trafficking ◽

Mammalian Cells ◽

Rho Gtpase ◽

Family Members ◽

Membrane Traffic ◽

Small Gtpases ◽

Endomembrane System ◽

Rho Family

In the endomembrane system of mammalian cells, membrane traffic processes require a high degree of regulation in order to ensure their specificity. The range of molecules that participate in trafficking events is truly vast, and much attention to date has been given to the Rab family of small GTPases. However, in recent years, a role in membrane traffic for members of the Rho GTPase family, in particular Cdc42, has emerged. This prompted us to develop and apply an image-based high-content screen, initially focussing on the Golgi complex, using RNA interference to systematically perturb each of the 21 Rho family members and assess their importance to the overall organisation of this organelle. Analysis of our data revealed previously unreported roles for two atypical Rho family members, RhoBTB1 and RhoBTB3, in membrane traffic events. We find that depletion of RhoBTB3 affects the morphology of the Golgi complex and causes changes in the trafficking speeds of carriers operating at the interface of the Golgi and endoplasmic reticulum. In addition, RhoBTB3 was found to be present on these carriers. Depletion of RhoBTB1 was also found to cause a disturbance to the Golgi architecture, however, this phenotype seems to be linked to endocytosis and retrograde traffic pathways. RhoBTB1 was found to be associated with early endosomal intermediates, and changes in the levels of RhoBTB1 not only caused profound changes to the organisation and distribution of endosomes and lysosomes, but also resulted in defects in the delivery of two different classes of cargo molecules to downstream compartments. Together, our data reveal new roles for these atypical Rho family members in the endomembrane system.

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Ypt1/Rab1 regulates Hrr25/CK1δ kinase activity in ER–Golgi traffic and macroautophagy

The Journal of Cell Biology ◽

10.1083/jcb.201408075 ◽

2015 ◽

Vol 210 (2) ◽

pp. 273-285 ◽

Cited By ~ 34

Author(s):

Juan Wang ◽

Saralin Davis ◽

Shekar Menon ◽

Jinzhong Zhang ◽

Jingzhen Ding ◽

...

Keyword(s):

Subcellular Localization ◽

Kinase Activity ◽

Family Members ◽

Membrane Traffic ◽

Casein Kinase ◽

Cell Stress ◽

Rab Gtpase ◽

Casein Kinase 1 ◽

Copii Vesicles ◽

Cellular Components

ER-derived COPII-coated vesicles are conventionally targeted to the Golgi. However, during cell stress these vesicles also become a membrane source for autophagosomes, distinct organelles that target cellular components for degradation. How the itinerary of COPII vesicles is coordinated on these pathways remains unknown. Phosphorylation of the COPII coat by casein kinase 1 (CK1), Hrr25, contributes to the directional delivery of ER-derived vesicles to the Golgi. CK1 family members are thought to be constitutively active kinases that are regulated through their subcellular localization. Instead, we show here that the Rab GTPase Ypt1/Rab1 binds and activates Hrr25/CK1δ to spatially regulate its kinase activity. Consistent with a role for COPII vesicles and Hrr25 in membrane traffic and autophagosome biogenesis, hrr25 mutants were defective in ER–Golgi traffic and macroautophagy. These studies are likely to serve as a paradigm for how CK1 kinases act in membrane traffic.

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Arf family GTPases: roles in membrane traffic and microtubule dynamics

Biochemical Society Transactions ◽

10.1042/bst0331269 ◽

2005 ◽

Vol 33 (6) ◽

pp. 1269-1272 ◽

Cited By ~ 55

Author(s):

R.A. Kahn ◽

L. Volpicelli-Daley ◽

B. Bowzard ◽

P. Shrivastava-Ranjan ◽

Y. Li ◽

...

Keyword(s):

Phylogenetic Analysis ◽

Family Members ◽

Membrane Traffic ◽

Microtubule Dynamics ◽

Database Mining ◽

Vesicle Traffic ◽

Adp Ribosylation ◽

Adp Ribosylation Factor ◽

In Cells

Database mining and phylogenetic analysis of the Arf (ADP-ribosylation factor) superfamily revealed the presence in mammals of at least 22 members, including the six Arfs, two Sars and 14 Arl (Arf-like) proteins. At least six Arf family members were found in very early eukaryotes, including orthologues of Arf, Sar, Arl2, Arl3, Arl6 and Arl8. While roles for Arfs in membrane traffic are well known, those for most of the Arls remain unknown. Depletion in cells of the most closely related human Arf proteins, Arf1–Arf5, reveals specificities among their cellular roles and suggests that they may function in pairs at different steps in endocytic and secretory membrane traffic. In addition, recent results from a number of laboratories suggest that several of the Arl proteins may be involved in different aspects of microtubule-dependent functions. Thus, a second major role for Arf family GTPases, that of regulating microtubules, is emerging. Because membrane traffic is often dependent upon movement of vesicles along microtubules this raises the possibility that these two fundamental functions of Arf family members, regulation of vesicle traffic and microtubule dynamics, diverged from one function of Arfs in the earliest cells that has continued to branch and allow additional levels of regulation.

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Effective Clinical Interviewing

Language Speech and Hearing Services in Schools ◽

10.1044/0161-1461.0904.265 ◽

1978 ◽

Vol 9 (4) ◽

pp. 265-271 ◽

Cited By ~ 1

Author(s):

Pauline T. Flynn

Keyword(s):

Family Members ◽

Essential Elements ◽

Speech Language Pathologist ◽

Lay Persons ◽

Clinical Interviewing ◽

Client Management

Speech, language, and hearing professionals rely on many individuals to provide information about a client. Management programs, in part, are devised, modified, and evaluated according to responses obtained from the client, family members, educators, and other professional and lay persons who have contact with the client. The speech-language pathologist has the responsibility of obtaining pertinent, complete, unbiased information about clients. This article provides an overview of the essential elements of an interview.

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Much Ado About Fried Chicken: Abetting Aspiration or Respecting Autonomy?

American Journal of Speech-Language Pathology ◽

10.1044/2019_ajslp-18-0207 ◽

2019 ◽

Vol 28 (3) ◽

pp. 1356-1362

Author(s):

Laurence Tan Lean Chin ◽

Yu Jun Lim ◽

Wan Ling Choo

Keyword(s):

Palliative Care ◽

End Of Life ◽

Multidisciplinary Team ◽

Biopsychosocial Model ◽

Family Members ◽

Clinical Decisions ◽

Goals Of Care ◽

Complex Needs ◽

Aspiration Risk ◽

Patient Centric

Purpose Palliative care is a philosophy of care that encompasses holistic, patient-centric care involving patients and their family members and loved ones. Palliative care patients often have complex needs. A common challenge in managing patients near their end of life is the complexity of navigating clinical decisions and finding achievable and realistic goals of care that are in line with the values and wishes of patients. This often results in differing opinions and conflicts within the multidisciplinary team. Conclusion This article describes a tool derived from the biopsychosocial model and the 4-quadrant ethical model. The authors describe the use of this tool in managing a patient who wishes to have fried chicken despite aspiration risk and how this tool was used to encourage discussions and reduce conflict and distress within the multidisciplinary team.

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A Strengths-Based Approach to Autism: Neurodiversity and Partnering With the Autism Community

Perspectives of the ASHA Special Interest Groups ◽

10.1044/persp2.sig1.56 ◽

2017 ◽

Vol 2 (1) ◽

pp. 56-68 ◽

Cited By ~ 8

Author(s):

Amy L. Donaldson ◽

Karen Krejcha ◽

Andy McMillin

Keyword(s):

Broad Spectrum ◽

First Language ◽

Family Members ◽

Community Identity ◽

Speech Language Pathologists

The autism community represents a broad spectrum of individuals, including those experiencing autism, their parents and/or caregivers, friends and family members, professionals serving these individuals, and other allies and advocates. Beliefs, experiences, and values across the community can be quite varied. As such, it is important for the professionals serving the autism community to be well-informed about current discussions occurring within the community related to neurodiversity, a strengths-based approach to partnering with autism community, identity-first language, and concepts such as presumed competence. Given the frequency with which speech-language pathologists (SLPs) serve the autism community, the aim of this article is to introduce and briefly discuss these topics.

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