Richard C. Johnson

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Incorporation of GluR1-containing AMPA receptors into synapses is essential to several forms of neural plasticity, including long-term potentiation (LTP). Numerous signaling pathways that trigger this process have been identified, but the direct modifications of GluR1 that control its incorporation into synapses are unclear. Here, we show that(More)
Spine function requires precise control of the actin cytoskeleton. Kalirin-7, a GDP/GTP exchange factor for Rac1, interacts with PDZ proteins such as PSD-95, colocalizing with PSD-95 at synapses of cultured hippocampal neurons. PSD-95 and Kalirin-7 interact in vivo and in heterologous expression systems. In primary cortical neurons, transfected Kalirin-7 is(More)
A recently described form of synaptic plasticity results in dynamic changes in the calcium permeability of synaptic AMPA receptors. Since the AMPA receptor GluR2 subunit confers calcium permeability, this plasticity is thought to occur through the dynamic exchange of synaptic GluR2-lacking and GluR2-containing receptors. To investigate the molecular(More)
Long-term potentiation (LTP), a well-characterized form of synaptic plasticity, has long been postulated as a cellular correlate of learning and memory. Although LTP can persist for long periods of time, the mechanisms underlying LTP maintenance, in the midst of ongoing protein turnover and synaptic activity, remain elusive. Sustained activation of the(More)
Communication between membranes and the actin cytoskeleton is an important aspect of neuronal function. Regulators of actin cytoskeletal dynamics include the Rho-like small GTP-binding proteins and their exchange factors. Kalirin is a brain-specific protein, first identified through its interaction with peptidylglycine-alpha-amidating monooxygenase. In this(More)
The actin cytoskeleton, essential for neuronal development, is regulated in part by small GTP binding proteins of the Rho subfamily. Kalirin-9, with two Rho subfamily-specific GDP/GTP exchange factor (GEF) domains, localizes to neurites and growth cones of primary cortical neurons. Kalirin-9 overexpression in cultured cortical neurons induces longer(More)
Kalirin is a neuron-specific GDP/GTP exchange factor for Rho subfamily GTP-binding proteins. The major Kalirin transcripts in adult rat brain were identified. Most include a Sec14p-like putative lipid-binding motif followed by nine spectrin-like repeats and a Dbl homology/pleckstrin homology (DH-PH) domain. Kalirin proteins with four different NH(2) termini(More)
Although the integral membrane proteins that catalyze steps in the biosynthesis of neuroendocrine peptides are known to contain routing information in their cytosolic domains, the proteins recognizing this routing information are not known. Using the yeast two-hybrid system, we previously identified P-CIP10 as a protein interacting with the cytosolic(More)
The adenomatous polyposis coli (APC) gene is a tumor suppressor gene that is mutated in human familial adenomatous polyposis, an autosomal dominant condition with predisposition to colorectal carcinoma and brain tumors. Although tumor suppressor genes appear to play a general role in regulating cellular proliferation, the normal biological function of the(More)
Nitric oxide (NO) acts as a neurotransmitter. However, excess NO produced from neuronal NO synthase (nNOS) or inducible NOS (iNOS) during inflammation of the central nervous system can be neurotoxic, disrupting neurotransmitter and hormone production and killing neurons. A screen of a hippocampal cDNA library showed that a unique region of the iNOS protein(More)