LAPORAN INDIVIDU PRAKTIK LAPANGAN TERBIMBING (PLT)

Universitas Negeri Yogyakarta (UNY) merupakan perguruan tinggi negeri berbasis pendidikan yang mempunyai tu gas untuk menyelenggarakan pendidikan dan pengabdian kepada masyarakat serta membinatenaga kependidikan. Untuk mewujudkan hal tersebut, maka UNY memberikan pengetahuan dan keterampilan kepada mahasiswa program studi pendidikan pada salah satu matakuliah yaitu Praktik LapanganTerbimbing (PLT). Praktik Lapangan Terbimbing (PLT) merupakan kesempatan bagi mahasiswa untuk mengaplikasi ilmu yang telah dipelajari di bangku perkuliahan serta menjadikan mahasiswa untuk mendapatkan pengalaman nyata dan langsung dalam pemberian ilmu Pendidikan Ilmu Pengetahuan Sosial (PIPS). Praktek Lapangan Terbimbing (PLT) dilaksanakan di SMP Negeri 3 Pakem yang beralamat di Pojok, Harjobinangun, Pakem, Sleman dimulai pada tanggal 15 September 2017 dan diakhiri pada tanggal 15 November 2017. Praktik Lapangan Terbimbing (PLT) merupakan kegiatan pembelajaran di sekolah. Pelaksanaan PLT ini dilakukan dengan mengajar di kelas selama kegiatan pembelajaran di sekolah tersebut sesuai jadwal yang sudahditentukan. Dengan adanya kegiatan PLT ini dapat dijadikan sebagai sarana untuk menjadikan diri sebagai guru atau pendidik yang professional yaitu guru yang mempunyai nilai, sikap, kemampuan dan ketrampilan yang memadai sesuai dengan bidangnya masing-masing

The glycolytic enzyme phosphofructokinase-1 assembles into filaments.

Despite abundant knowledge of the regulation and biochemistry of glycolytic enzymes, we have limited understanding on how they are spatially organized in the cell. Emerging evidence indicates that nonglycolytic metabolic enzymes regulating diverse pathways can assemble into polymers. We now show tetramer- and substrate-dependent filament assembly by phosphofructokinase-1 (PFK1), which is considered the "gatekeeper" of glycolysis because it catalyzes the step committing glucose to breakdown. Recombinant liver PFK1 (PFKL) isoform, but not platelet PFK1 (PFKP) or muscle PFK1 (PFKM) isoforms, assembles into filaments. Negative-stain electron micrographs reveal that filaments are apolar and made of stacked tetramers oriented with exposed catalytic sites positioned along the edge of the polymer. Electron micrographs and biochemical data with a PFKL/PFKP chimera indicate that the PFKL regulatory domain mediates filament assembly. Quantified live-cell imaging shows dynamic properties of localized PFKL puncta that are enriched at the plasma membrane. These findings reveal a new behavior of a key glycolytic enzyme with insights on spatial organization and isoform-specific glucose metabolism in cells

Conformational rearrangement of the NMDA receptor amino-terminal domain during activation and allosteric modulation.

N-Methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors essential for synaptic plasticity and memory. Receptor activation involves glycine- and glutamate-stabilized closure of the GluN1 and GluN2 subunit ligand binding domains that is allosterically regulated by the amino-terminal domain (ATD). Using single molecule fluorescence resonance energy transfer (smFRET) to monitor subunit rearrangements in real-time, we observe a stable ATD inter-dimer distance in the Apo state and test the effects of agonists and antagonists. We find that GluN1 and GluN2 have distinct gating functions. Glutamate binding to GluN2 subunits elicits two identical, sequential steps of ATD dimer separation. Glycine binding to GluN1 has no detectable effect, but unlocks the receptor for activation so that glycine and glutamate together drive an altered activation trajectory that is consistent with ATD dimer separation and rotation. We find that protons exert allosteric inhibition by suppressing the glutamate-driven ATD separation steps, and that greater ATD separation translates into greater rotation and higher open probability

Conformational rearrangement of the NMDA receptor amino-terminal domain during activation and allosteric modulation.

N-Methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors essential for synaptic plasticity and memory. Receptor activation involves glycine- and glutamate-stabilized closure of the GluN1 and GluN2 subunit ligand binding domains that is allosterically regulated by the amino-terminal domain (ATD). Using single molecule fluorescence resonance energy transfer (smFRET) to monitor subunit rearrangements in real-time, we observe a stable ATD inter-dimer distance in the Apo state and test the effects of agonists and antagonists. We find that GluN1 and GluN2 have distinct gating functions. Glutamate binding to GluN2 subunits elicits two identical, sequential steps of ATD dimer separation. Glycine binding to GluN1 has no detectable effect, but unlocks the receptor for activation so that glycine and glutamate together drive an altered activation trajectory that is consistent with ATD dimer separation and rotation. We find that protons exert allosteric inhibition by suppressing the glutamate-driven ATD separation steps, and that greater ATD separation translates into greater rotation and higher open probability

Conformational pathway provides unique sensitivity to a synaptic mGluR.

Metabotropic glutamate receptors (mGluRs) are dimeric G-protein-coupled receptors that operate at synapses. Macroscopic and single molecule FRET to monitor structural rearrangements in the ligand binding domain (LBD) of the mGluR7/7 homodimer revealed it to have an apparent affinity ~4000-fold lower than other mGluRs and a maximal activation of only ~10%, seemingly too low for activation at synapses. However, mGluR7 heterodimerizes, and we find it to associate with mGluR2 in the hippocampus. Strikingly, the mGluR2/7 heterodimer has high affinity and efficacy. mGluR2/7 shows cooperativity in which an unliganded subunit greatly enhances activation by agonist bound to its heteromeric partner, and a unique conformational pathway to activation, in which mGluR2/7 partially activates in the Apo state, even when its LBDs are held open by antagonist. High sensitivity and an unusually broad dynamic range should enable mGluR2/7 to respond to both glutamate transients from nearby release and spillover from distant synapses

Conformational pathway provides unique sensitivity to a synaptic mGluR

International audienceMetabotropic glutamate receptors (mGluRs) are dimeric G-protein-coupled receptors that operate at synapses. Macroscopic and single molecule FRET to monitor structural rearrangements in the ligand binding domain (LBD) of the mGluR7/7 homodimer revealed it to have an apparent affinity~4000-fold lower than other mGluRs and a maximal activation of onlỹ 10%, seemingly too low for activation at synapses. However, mGluR7 heterodimerizes, and we find it to associate with mGluR2 in the hippocampus. Strikingly, the mGluR2/7 hetero-dimer has high affinity and efficacy. mGluR2/7 shows cooperativity in which an unliganded subunit greatly enhances activation by agonist bound to its heteromeric partner, and a unique conformational pathway to activation, in which mGluR2/7 partially activates in the Apo state, even when its LBDs are held open by antagonist. High sensitivity and an unusually broad dynamic range should enable mGluR2/7 to respond to both glutamate transients from nearby release and spillover from distant synapses