scholarly journals PAR3 and aPKC regulate Golgi organization through CLASP2 phosphorylation to generate cell polarity

2015 ◽  
Vol 26 (4) ◽  
pp. 751-761 ◽  
Author(s):  
Toshinori Matsui ◽  
Takashi Watanabe ◽  
Kenji Matsuzawa ◽  
Mai Kakeno ◽  
Nobumasa Okumura ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Golgi Apparatus ◽  
Cell Polarity ◽  
Cross Talk ◽  
Cell Polarization ◽  
Trans Golgi Network ◽  
Golgi Ribbon ◽  
Golgi Network ◽  
Golgi Organization

The organization of the Golgi apparatus is essential for cell polarization and its maintenance. The polarity regulator PAR complex (PAR3, PAR6, and aPKC) plays critical roles in several processes of cell polarization. However, how the PAR complex participates in regulating the organization of the Golgi remains largely unknown. Here we demonstrate the functional cross-talk of the PAR complex with CLASP2, which is a microtubule plus-end–tracking protein and is involved in organizing the Golgi ribbon. CLASP2 directly interacted with PAR3 and was phosphorylated by aPKC. In epithelial cells, knockdown of either PAR3 or aPKC induced the aberrant accumulation of CLASP2 at the trans-Golgi network (TGN) concomitantly with disruption of the Golgi ribbon organization. The expression of a CLASP2 mutant that inhibited the PAR3-CLASP2 interaction disrupted the organization of the Golgi ribbon. CLASP2 is known to localize to the TGN through its interaction with the TGN protein GCC185. This interaction was inhibited by the aPKC-mediated phosphorylation of CLASP2. Furthermore, the nonphosphorylatable mutant enhanced the colocalization of CLASP2 with GCC185, thereby perturbing the Golgi organization. On the basis of these observations, we propose that PAR3 and aPKC control the organization of the Golgi through CLASP2 phosphorylation.

scholarly journals Actin dynamics coupled to clathrin-coated vesicle formation at the trans-Golgi network

2004 ◽  
Vol 165 (6) ◽  
pp. 781-788 ◽  
Author(s):  
Sebastien Carreno ◽  
Åsa E. Engqvist-Goldstein ◽  
Claire X. Zhang ◽  
Kent L. McDonald ◽  
David G. Drubin
Keyword(s):  
Time Lapse ◽  
Actin Dynamics ◽  
Coated Vesicle ◽  
Cell Cortex ◽  
Actin Assembly ◽  
Trans Golgi Network ◽  
Lysosome Biogenesis ◽  
Diverse Species ◽  
Golgi Network ◽  
Golgi Organization

In diverse species, actin assembly facilitates clathrin-coated vesicle (CCV) formation during endocytosis. This role might be an adaptation specific to the unique environment at the cell cortex, or it might be fundamental, facilitating CCV formation on different membranes. Proteins of the Sla2p/Hip1R family bind to actin and clathrin at endocytic sites in yeast and mammals. We hypothesized that Hip1R might also coordinate actin assembly with clathrin budding at the trans-Golgi network (TGN). Using deconvolution and time-lapse microscopy, we showed that Hip1R is present on CCVs emerging from the TGN. These vesicles contain the mannose 6-phosphate receptor involved in targeting proteins to the lysosome, and the actin nucleating Arp2/3 complex. Silencing of Hip1R expression by RNAi resulted in disruption of Golgi organization and accumulation of F-actin structures associated with CCVs on the TGN. Hip1R silencing and actin poisons slowed cathepsin D exit from the TGN. These studies establish roles for Hip1R and actin in CCV budding from the TGN for lysosome biogenesis.

Identification of a di-leucine motif within the C terminus domain of the Menkes disease protein that mediates endocytosis from the plasma membrane

1999 ◽  
Vol 112 (11) ◽  
pp. 1721-1732 ◽  
Author(s):  
M.J. Francis ◽  
E.E. Jones ◽  
E.R. Levy ◽  
R.L. Martin ◽  
S. Ponnambalam ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Transmembrane Domain ◽  
Menkes Disease ◽  
Cytoplasmic Domain ◽  
Endocytic Pathway ◽  
Site Directed Mutagenesis ◽  
Trans Golgi Network ◽  
C Terminus ◽  
Golgi Network

The protein encoded by the Menkes disease gene (MNK) is localised to the Golgi apparatus and cycles between the trans-Golgi network and the plasma membrane in cultured cells on addition and removal of copper to the growth medium. This suggests that MNK protein contains active signals that are involved in the retention of the protein to the trans-Golgi network and retrieval of the protein from the plasma membrane. Previous studies have identified a signal involved in Golgi retention within transmembrane domain 3 of MNK. To identify a motif sufficient for retrieval of MNK from the plasma membrane, we analysed the cytoplasmic domain, downstream of transmembrane domain 7 and 8. Chimeric constructs containing this cytoplasmic domain fused to the reporter molecule CD8 localised the retrieval signal(s) to 62 amino acids at the C terminus. Further studies were performed on putative internalisation motifs, using site-directed mutagenesis, protein expression, chemical treatment and immunofluorescence. We observed that a di-leucine motif (L1487L1488) was essential for rapid internalisation of chimeric CD8 proteins and the full-length Menkes cDNA from the plasma membrane. We suggest that this motif mediates the retrieval of MNK from the plasma membrane into the endocytic pathway, via the recycling endosomes, but is not sufficient on its own to return the protein to the Golgi apparatus. These studies provide a basis with which to identify other motifs important in the sorting and delivery of MNK from the plasma membrane to the Golgi apparatus.

BFA-induced compartments from the Golgi apparatus and trans-Golgi network/early endosome are distinct in plant cells

2009 ◽  
Vol 60 (5) ◽  
pp. 865-881 ◽  
Author(s):  
Sheung Kwan Lam ◽  
Yi Cai ◽  
Yu Chung Tse ◽  
Juan Wang ◽  
Angus Ho Yin Law ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Plant Cells ◽  
Early Endosome ◽  
Trans Golgi Network ◽  
Golgi Network

scholarly journals Intracellular movement of two mannose 6-phosphate receptors: return to the Golgi apparatus.

1988 ◽  
Vol 106 (3) ◽  
pp. 617-628 ◽  
Author(s):  
J R Duncan ◽  
S Kornfeld
Keyword(s):  
Sialic Acid ◽  
Golgi Apparatus ◽  
Chinese Hamster ◽  
Murine Lymphoma ◽  
Trans Golgi Network ◽  
Intracellular Movement ◽  
Golgi Region ◽  
Golgi Compartment ◽  
Mannose 6 Phosphate ◽  
Golgi Network

We have used Chinese hamster ovary (CHO) cells and a murine lymphoma cell line to study the recycling of the 215-kD and the 46-kD mannose 6-phosphate receptors to various regions of the Golgi to determine the site where the receptors first encounter newly synthesized lysosomal enzymes. For assessing return to the trans-most Golgi compartments containing sialyltransferase (trans-cisternae and trans-Golgi network), the oligosaccharides of receptor molecules on the cell surface were labeled with [3H]galactose at 4 degrees C. Upon warming to 37 degrees C, the [3H]galactose residues on both receptors were substituted with sialic acid with a t1/2 approximately 3 hrs. Other glycoproteins acquired sialic acid at least 8-10 times slower. Return of the receptors to the trans-Golgi cisternae containing galactosyltransferase could not be detected. Return to the cis/middle Golgi cisternae containing alpha-mannosidase I was measured by adding deoxymannojirimycin, a mannosidase I inhibitor, during the initial posttranslational passage of [3H]mannose-labeled glycoproteins through the Golgi, thereby preserving oligosaccharides which would be substrates for alpha-mannosidase I. After removal of the inhibitor, return to the early Golgi with subsequent passage through the Golgi complex was measured by determining the conversion of the oligosaccharides from high mannose to complex-type units. This conversion was very slow for the receptors and other glycoproteins (t1/2 approximately 20 h). Exposure of the receptors and other glycoproteins to the dMM-sensitive alpha-mannosidase without movement through the Golgi apparatus was determined by measuring the loss of mannose residues from these proteins. This loss was also slow. These results indicate that both Man-6-P receptors routinely return to the Golgi compartment which contains sialyltransferase and recycle through other regions of the Golgi region less frequently. We infer that the trans-Golgi network is the major site for lysosomal enzyme sorting in CHO and murine lymphoma cells.

scholarly journals Glucose regulates clathrin adaptors at the trans-Golgi network and endosomes

2011 ◽  
Vol 22 (19) ◽  
pp. 3671-3683 ◽  
Author(s):  
Quyen L. Aoh ◽  
Lee M. Graves ◽  
Mara C. Duncan
Keyword(s):  
Cell Polarity ◽  
Translation Initiation ◽  
Posttranslational Modifications ◽  
Raw Material ◽  
Eukaryotic Cells ◽  
Glucose Starvation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Trans Golgi Network ◽  
Golgi Network ◽  
Biomass Increase

Glucose is a rich source of energy and the raw material for biomass increase. Many eukaryotic cells remodel their physiology in the presence and absence of glucose. The yeast Saccharomyces cerevisiae undergoes changes in transcription, translation, metabolism, and cell polarity in response to glucose availability. Upon glucose starvation, translation initiation and cell polarity are immediately inhibited, and then gradually recover. In this paper, we provide evidence that, as in cell polarity and translation, traffic at the trans-Golgi network (TGN) and endosomes is regulated by glucose via an unknown mechanism that depends on protein kinase A (PKA). Upon glucose withdrawal, clathrin adaptors exhibit a biphasic change in localization: they initially delocalize from the membrane within minutes and later partially recover onto membranes. Additionally, the removal of glucose induces changes in posttranslational modifications of adaptors. Ras and Gpr1 signaling pathways, which converge on PKA, are required for changes in adaptor localization and changes in posttranslational modifications. Acute inhibition of PKA demonstrates that inhibition of PKA prior to glucose withdrawal prevents several adaptor responses to starvation. This study demonstrates that PKA activity prior to glucose starvation primes membrane traffic at the TGN and endosomes in response to glucose starvation.

Sign in / Sign up

Export Citation Format

Share Document