Yeast mutants affecting possible quality control of plasma membrane proteins
UMass Chan AffiliationsDepartment of Molecular Genetics and Microbiology
Graduate School of Biomedical Sciences
Document TypeJournal Article
KeywordsAmino Acid Sequence; *Amino Acid Transport Systems; Amino Acid Transport Systems, Basic; Cell Membrane; Cloning, Molecular; Endosomes; Fungal Proteins; Green Fluorescent Proteins; Luminescent Proteins; Membrane Proteins; Membrane Transport Proteins; Microscopy, Fluorescence; Molecular Sequence Data; Mutation; Peptides; Protein Folding; Receptors, Cell Surface; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Sequence Homology, Amino Acid; Suppression, Genetic
Medicine and Health Sciences
MetadataShow full item record
AbstractMutations gef1, stp22, STP26, and STP27 in Saccharomyces cerevisiae were identified as suppressors of the temperature-sensitive alpha-factor receptor (mutation ste2-3) and arginine permease (mutation can1(ts)). These suppressors inhibited the elimination of misfolded receptors (synthesized at 34 degrees C) as well as damaged surface receptors (shifted from 22 to 34 degrees C). The stp22 mutation (allelic to vps23 [M. Babst and S. Emr, personal communication] and the STP26 mutation also caused missorting of carboxypeptidase Y, and ste2-3 was suppressed by mutations vps1, vps8, vps10, and vps28 but not by mutation vps3. In the stp22 mutant, both the mutant and the wild-type receptors (tagged with green fluorescent protein [GFP]) accumulated within an endosome-like compartment and were excluded from the vacuole. GFP-tagged Stp22p also accumulated in this compartment. Upon reaching the vacuole, cytoplasmic domains of both mutant and wild-type receptors appeared within the vacuolar lumen. Stp22p and Gef1p are similar to tumor susceptibility protein TSG101 and voltage-gated chloride channel, respectively. These results identify potential elements of plasma membrane quality control and indicate that cytoplasmic domains of membrane proteins are translocated into the vacuolar lumen.
Mol Cell Biol. 1999 May;19(5):3588-99.
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/34034
Showing items related by title, author, creator and subject.
Dynamic Regulation at the Neuronal Plasma Membrane: Novel Endocytic Mechanisms Control Anesthetic-Activated Potassium Channels and Amphetamine-Sensitive Dopamine Transporters: A DissertationGabriel, Luke R. (2013-06-13)Endocytic trafficking dynamically regulates neuronal plasma membrane protein presentation and activity, and plays a central role in excitability and plasticity. Over the course of my dissertation research I investigated endocytic mechanisms regulating two neuronal membrane proteins: the anesthetic-activated potassium leak channel, KCNK3, as well as the psychostimulant-sensitive dopamine transporter (DAT). My results indicate that KCNK3 internalizes in response to Protein Kinase C (PKC) activation, using a novel pathway that requires the phosphoserine binding protein, 14-3-3β, and demonstrates for the first time regulated KCNK3 channel trafficking in neurons. Additionally, PKC-mediated KCNK3 trafficking requires a non-canonical endocytic motif, which is shared exclusively between KCNK3 and sodium-dependent neurotransmitter transporters, such as DAT. DAT trafficking studies in intact ex vivo adult striatal slices indicate that DAT endocytic trafficking has both dynamin-dependent and –independent components. Moreover, DAT segregates into two populations at the neuronal plasma membrane: trafficking-competent and -incompetent. Taken together, these results demonstrate that novel, non-classical endocytic mechanisms dynamically control the plasma membrane presentation of these two important neuronal proteins.
Selective interaction of JNK protein kinase isoforms with transcription factorsGupta, Shashi; Barrett, Tamera; Whitmarsh, Alan J.; Cavanagh, Julie; Sluss, Hayla Karen; Derijard, Benoit; Davis, Roger J. (1996-06-03)The JNK protein kinase is a member of the MAP kinase group that is activated in response to dual phosphorylation on threonine and tyrosine. Ten JNK isoforms were identified in human brain by molecular cloning. These protein kinases correspond to alternatively spliced isoforms derived from the JNK1, JNK2 and JNK3 genes. The protein kinase activity of these JNK isoforms was measured using the transcription factors ATF2, Elk-1 and members of the Jun family as substrates. Treatment of cells with interleukin-1 (IL-1) caused activation of the JNK isoforms. This activation was blocked by expression of the MAP kinase phosphatase MKP-1. Comparison of the binding activity of the JNK isoforms demonstrated that the JNK proteins differ in their interaction with ATF2, Elk-1 and Jun transcription factors. Individual members of the JNK group may therefore selectively target specific transcription factors in vivo.
Role of the Raf/mitogen-activated protein kinase pathway in p21ras desensitizationKlarlund, Jes K.; Cherniack, Andrew D.; McMahon, Martin; Czech, Michael P. (1996-07-12)Desensitization of p21(ras) after stimulation of cells by growth factors and phorbol 12-myristate 13-acetate (PMA) correlates with hyperphosphorylation of the guanine nucleotide exchange factor Son-of-sevenless (Sos) and its dissociation from the adaptor protein Grb2 (Cherniack, A., Klarlund, J. K., Conway, B. R., and Czech, M. P. (1995) J. Biol. Chem. 270, 1485-1488). To test the role of the Raf/mitogen-activated protein (MAP) kinase pathway, we utilized cells expressing a chimera composed of the catalytic domain of p74Raf-1 and the hormone binding domain of the estradiol receptor (DeltaRaf-1:ER). Estradiol markedly stimulated DeltaRaf-1:ER and the downstream MEK and MAP kinases in these cells as well as Sos phosphorylation. However, the dissociation of Grb2 from Sos observed in response to PMA was not apparent upon DeltaRaf-1:ER activation. Furthermore, stimulation of DeltaRaf-1:ER did not impair GTP loading of p21(ras) in response to platelet-derived growth factor or epidermal growth factor. We conclude that activation of the Raf/MAP kinase pathway alone in these cells is insufficient to cause disassembly of Sos from Grb2 or to interrupt the ability of Sos to catalyze activation of p21(ras).