Search results for "binding proteins"

EFFECTS OF THYROID HORMONES ON RNA-BINDING PROTEINS EXPRESSED IN DEVELOPING RAT BRAIN

2005

Developing rat brain as well as cultured astrocytes contain H1° mRNA-protein complexes

2015

RNA-binding proteins (RBPs) regulate intracellular transport, pre-localization, stability, and translation of mRNAs [1]. We previously identified a set of proteins which interact with mRNAs encoding H1° and H3.3 histones [2-5]. All these proteins are probably part of a ribonucleoprotein particle [6]. Here we report the results of a more detailed study on the expression and intracellular localization of some of these RBPs, such as hnRNP K and A1, and Hsc70, during rat brain development and in cultured rat astrocytes. We also investigated the presence in the complexes of PIPPin/CSD-C2 protein. Affinity chromatography was performed as already described [6]. Preparation of total lysates and cel…

Reconstitution of vesicular transport to Rab11-positive recycling endosomes in vitro.

2003

Rab GTPases are key regulators of vesicular protein transport in both the endocytic and exocytic pathways. In endocytosis and recycling, Rab11 plays a role in receptor recycling to plasma membrane via the pericentriolar recycling compartment. However, little is known about the molecular requirements and partners that promote transport through Rab11-positive recycling endosomes. Here, we report a novel approach to reconstitute transport to immunoabsorbed recycling endosomes in vitro. We show that transport is temperature-, energy-, and time-dependent and requires the presence of Rab proteins, as it is inhibited by the Rab-interacting protein Rab GDP-dissociation inhibitor that removes Rab pr…

Alcadein cleavages by amyloid beta-precursor protein (APP) alpha- and gamma-secretases generate small peptides, p3-Alcs, indicating Alzheimer disease…

2009

Alcadeins (Alcs) constitute a family of neuronal type I membrane proteins, designated Alc(alpha), Alc(beta), and Alc(gamma). The Alcs express in neurons dominantly and largely colocalize with the Alzheimer amyloid precursor protein (APP) in the brain. Alcs and APP show an identical function as a cargo receptor of kinesin-1. Moreover, proteolytic processing of Alc proteins appears highly similar to that of APP. We found that APP alpha-secretases ADAM 10 and ADAM 17 primarily cleave Alc proteins and trigger the subsequent secondary intramembranous cleavage of Alc C-terminal fragments by a presenilin-dependent gamma-secretase complex, thereby generating "APP p3-like" and non-aggregative Alc pe…

Arabidopsis p24δ5 and p24δ9 facilitate Coat Protein I-dependent transport of the K/HDEL receptor ERD2 from the Golgi to the endoplasmic reticulum.

2014

The p24 proteins belong to a family of type I membrane proteins which cycle between the endoplasmic reticulum (ER) and Golgi via coat protein I (COPI) and COPII vesicles. Current nomenclature classifies them into four subfamilies, although plant p24 proteins belong to either the p24β or the p24δ subfamilies. Here, we show that Arabidopsis p24δ5/δ9 and HDEL ligands shift the steady-state distribution of the K/HDEL receptor ERD2 from the Golgi to the ER. We also show that p24δ5/δ9 interact directly with ERD2. This interaction requires the Golgi dynamics (GOLD) domain in p24δ5 and is much higher at acidic than at neutral pH, consistent with both proteins interacting at the cis-Golgi. In additi…

Requirement of Retinoic Acid Receptor Isotypes α, β, and γ during the Initial Steps of Neural Differentiation of PCC7 Cells

2005

Retinoic acid (RA) is indispensable for morphogenesis and differentiation of several tissues, including the nervous system. The requirement of the RA receptor (RAR) isotypes alpha, beta, and gamma and the putative role of retinoid X receptor-(RXR) signaling in RA-induced neural differentiation, was analyzed. For this compound-selective retinoids and the murine embryonal carcinoma cell line PCC7, a model system for RA-dependent neural differentiation was used. The present paper shows that proliferating PCC7 cells primarily express RXRalpha and RARalpha, lower levels of RXRbeta, and barely detectable amounts of RARbeta, RARgamma, and RXRgamma. At receptor-selective concentrations, only a RARa…

Xanthine dehydrogenase processes retinol to retinoic acid in human mammary epithelial cells

2008

Retinoic acid is considered to be the active metabolite of retinol, able to control differentiation and proliferation of epithelia. Retinoic acid biosynthesis has been widely described with the implication of multiple enzymatic activities. However, our understanding of the cell biological function and regulation of this process is limited. In a recent study we evidenced that milk xanthine oxidase (E.C. 1.17.3.2.) is capable to oxidize all-trans-retinol bound to CRBP (holo-CRBP) to all-trans-retinaldehyde and then to all-trans-retinoic acid. To get further knowledge regarding this process we have evaluated the biosynthetic pathway of retinoic acid in a human mammary epithelial cell line (HME…

Antagonistic feedback loops involving Rau and Sprouty in the Drosophila eye control neuronal and glial differentiation.

2013

During development, differentiation is often initiated by the activation of different receptor tyrosine kinases (RTKs), which results in the tightly regulated activation of cytoplasmic signaling cascades. In the differentiation of neurons and glia in the developing Drosophila eye, we found that the proper intensity of RTK signaling downstream of fibroblast growth factor receptor (FGFR) or epidermal growth factor receptor required two mutually antagonistic feedback loops. We identified a positive feedback loop mediated by the Ras association (RA) domain-containing protein Rau that sustained Ras activity and counteracted the negative feedback loop mediated by Sprouty. Rau has two RA domains t…

The differentiation of the serotonergic neurons in the Drosophila ventral nerve cord depends on the combined function of the zinc finger proteins Eag…

1997

ABSTRACT The Drosophila ventral nerve cord (vNC) derives from a stereotyped population of neural stem cells, neuroblasts (NBs), each of which gives rise to a characteristic cell lineage. The mechanisms leading to the specification and differentiation of these lineages are largely unknown. Here we analyse mechanisms leading to cell differentiation within the NB 7-3 lineage. Analogous to the grasshopper, NB 7-3 is the progenitor of the Drosophila vNC serotonergic neurons. The zinc finger protein Eagle (Eg) is expressed in NB 7-3 just after delamination and is present in all NB 7-3 progeny until late stage 17. DiI cell lineage tracing and immunocytochemistry reveal that eg is required for norm…

Species-specific mechanisms for cholesterol 7alpha-hydroxylase (CYP7A1) regulation by drugs and bile acids.

2005

The gene encoding cholesterol 7alpha-hydroxylase (CYP7A1) is tightly regulated in order to control intrahepatic cholesterol and bile acid levels. Ligands of the xenobiotic-sensing pregnane X receptor inhibit CYP7A1 expression. To retrace the evolution of the molecular mechanisms underlying CYP7A1 inhibition, we used a chicken hepatoma cell system that retains the ability to be induced by phenobarbital and other drugs. Whereas bile acids regulate CYP7A1 via small heterodimer partner and liver receptor homolog-1, mRNA expression of these nuclear receptors is unchanged by xenobiotics. Instead, drugs repress chicken hepatic nuclear factor 4alpha (HNF4alpha) transcript levels concomitant with a …