Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.6.4.4 (kinesin)
5,033 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The cargo that the molecular motor kinesin moves along microtubules has been elusive. We searched for binding partners of the COOH terminus of kinesin light chain, which contains tetratricopeptide repeat (TPR) motifs. Three proteins were found, the c-jun NH(2)-terminal kinase (JNK)-interacting proteins (JIPs) JIP-1, JIP-2, and JIP-3, which are scaffolding proteins for the JNK signaling pathway. Concentration of JIPs in nerve terminals requires kinesin, as evident from the analysis of JIP COOH-terminal mutants and dominant negative kinesin constructs. Coprecipitation experiments suggest that kinesin carries the JIP scaffolds preloaded with cytoplasmic (dual leucine zipper-bearing kinase) and transmembrane signaling molecules (the Reelin receptor, ApoER2). These results demonstrate a direct interaction between conventional kinesin and a cargo, indicate that motor proteins are linked to their membranous cargo via scaffolding proteins, and support a role for motor proteins in spatial regulation of signal transduction pathways.
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PMID:Cargo of kinesin identified as JIP scaffolding proteins and associated signaling molecules. 1123 67

The transmembrane protein amyloid-beta precursor protein (APP) and the vesicle-associated protein c-Jun NH(2)-terminal kinase-interacting protein-1 (JIP-1) are transported into axons by kinesin-1. Both proteins may bind to kinesin-1 directly and can be transported separately. Because JIP-1 and APP can interact, kinesin-1 may recruit them as a complex, enabling their cotransport. In this study, we tested whether APP and JIP-1 are transported together or separately on different vesicles. We found that, within the cellular context, JIP-1 preferentially interacts with Thr(668)-phosphorylated APP (pAPP), compared with nonphosphorylated APP. In neurons, JIP-1 colocalizes with vesicles containing pAPP and is excluded from those containing nonphosphorylated APP. The accumulation of JIP-1 and pAPP in neurites requires kinesin-1, and the expression of a phosphomimetic APP mutant increases JIP-1 transport. Down-regulation of JIP-1 by small interfering RNA specifically impairs transport of pAPP, with no effect on the trafficking of nonphosphorylated APP. These results indicate that the phosphorylation of APP regulates the formation of a pAPP-JIP-1 complex that accumulates in neurites independent of nonphosphorylated APP.
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PMID:Coordinated transport of phosphorylated amyloid-beta precursor protein and c-Jun NH2-terminal kinase-interacting protein-1. 1630 30

In a genetic screen for Kinesin heavy chain (Khc)-interacting proteins, we identified APLIP1, a neuronally expressed Drosophila homolog of JIP-1, a JNK scaffolding protein . JIP-1 and its homologs have been proposed to act as physical linkers between kinesin-1, which is a plus-end-directed microtubule motor, and certain anterograde vesicles in the axons of cultured neurons . Mutation of Aplip1 caused larval paralysis, axonal swellings, and reduced levels of both anterograde and retrograde vesicle transport, similar to the effects of kinesin-1 inhibition. In contrast, Aplip1 mutation caused a decrease only in retrograde transport of mitochondria, suggesting inhibition of the minus-end microtubule motor cytoplasmic dynein . Consistent with dynein defects, combining heterozygous mutations in Aplip1 and Dynein heavy chain (Dhc64C) generated synthetic axonal transport phenotypes. Thus, APLIP1 may be an important part of motor-cargo linkage complexes for both kinesin-1 and dynein. However, it is also worth considering that APLIP1 and its associated JNK signaling proteins could serve as an important signaling module for regulating transport by the two opposing motors.
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PMID:APLIP1, a kinesin binding JIP-1/JNK scaffold protein, influences the axonal transport of both vesicles and mitochondria in Drosophila. 1633 40

Microtubules in neurites undergo multiple post-translational modifications. Recent work shows that neurites enriched in acetylated microtubules selectively support kinesin-mediated transport of the JNK regulator JIP-1 to growth cones.
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PMID:Microtubule modification: acetylation speeds anterograde traffic flow. 1708 3

Islet-brain 1 [IB1; also termed c-Jun N-terminal kinase (JNK)-interacting protein 1 (JIP-1] is involved in the apoptotic signaling cascade of JNK and functions as a scaffold protein. It organizes several MAP kinases and the microtubule-transport motor protein kinesin and relates to other signal-transducing molecules such as the amyloid precursor protein. Here we have identified IB1/JIP-1 using different antibodies that reacted with either a monomeric or a dimeric form of IB1/JIP-1. By immunoelectron microscopy, differences in the subcellular localization were observed. The monomeric form was found in the cytoplasmic compartment and is associated with the cytoskeleton and with membranes, whereas the dimeric form was found in addition in nuclei. After treatment of mouse brain homogenates with alkaline phosphatase, the dimeric form disappeared and the monomeric form decreased its molecular weight, suggesting that an IB1/JIP-1 dimerization is phosphorylation dependent and that IB1 exists in several phospho- forms. N-methyl-D-aspartate receptor activation induced a dephosphorylation of IB1/JIP-1 in primary cultures of cortical neurons and reduced homodimerization. In conclusion, these data suggest that IB1/JIP-1 monomers and dimers may differ in compartmental localization and thus function as a scaffold protein of the JNK signaling cascade in the cytoplasm or as a transcription factor in nuclei.
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PMID:Phosphorylation-dependent dimerization and subcellular localization of islet-brain 1/c-Jun N-terminal kinase-interacting protein 1. 1766 63

Amyloid-beta protein precursor (AbetaPP) is a receptor-like, type-I membrane protein that plays a central role in the pathogenesis of Alzheimer's disease. The cytoplasmic domain of AbetaPP is important for the metabolism and physiological functions of AbetaPP and contains a GYENPTY motif that interacts with proteins that contain a phosphotyrosine binding (PTB) domain such as X11/Mint, FE65, and the JIP family of proteins. X11 and X11-like proteins are neuronal adaptor proteins involved in presynaptic function and the intracellular trafficking of proteins. Recent studies in X11s knockout mice confirmed findings from in vitro studies that X11 proteins affect AbetaPP metabolism and the generation of amyloid-beta peptide. FE65 proteins are involved in transactivation in coordination with the intracellular domain fragment of AbetaPP, and/or in cellular responses to DNA damage. Neurodevelopmental defects observed in FE65s double knockout mice suggest that FE65 proteins cooperate with AbetaPP to play a role in neuronal cytoskeletal regulation. c-Jun N-terminal kinase (JNK) interacting protein-1 (JIP-1), a scaffolding protein for the JNK kinase cascade, has been suggested to mediate the intracellular trafficking of AbetaPP by molecular motor kinesin-1. This article reviews some of the recent findings regarding the regulation of physiological function and metabolism of AbetaPP by AbetaPP binding proteins.
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PMID:Regulation of the physiological function and metabolism of AbetaPP by AbetaPP binding proteins. 1958 34

Deficiency of caytaxin results in hereditary ataxia or dystonia in humans, mice and rats. Our yeast two-hybrid screen identified kinesin light chains (KLCs) as caytaxin-binding proteins. The tetratricopeptide-repeat region of KLC1 recognizes the ELEWED sequence (amino acids 115-120) of caytaxin. This motif is conserved among BNIP-2 family members and other KLC-interacting kinesin cargo proteins such as calsyntenins. Caytaxin associates with kinesin heavy chains (KHCs) indirectly by binding to KLCs, suggesting that caytaxin binds to the tetrameric kinesin molecule. In cultured hippocampal neurons, we found that caytaxin is distributed in both axons and dendrites in punctate patterns, and it colocalizes with microtubules and KHC. GFP-caytaxin expressed in hippocampal neurons is transported at a speed ( approximately 1 mum/second) compatible with kinesin movement. Inhibition of kinesin-1 by dominant-negative KHC decreases the accumulation of caytaxin in the growth cone. Caytaxin puncta do not coincide with vesicles containing known kinesin cargos such as APP or JIP-1. A part of caytaxin, however, colocalizes with mitochondria and suppression of caytaxin expression by RNAi redistributes mitochondria away from the distal ends of neurites. These data indicate that caytaxin binds to kinesin-1 and functions as an adaptor that mediates intracellular transport of specific cargos, one of which is the mitochondrion.
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PMID:Cayman ataxia protein caytaxin is transported by kinesin along neurites through binding to kinesin light chains. 1986 99

The molecular mechanisms underlying microtubule participation in autophagy are not known. In this study, we show that starvation-induced autophagosome formation requires the most dynamic microtubule subset. Upon nutrient deprivation, labile microtubules specifically recruit markers of autophagosome formation like class III-phosphatidylinositol kinase, WIPI-1, the Atg12-Atg5 conjugate, and LC3-I, whereas mature autophagosomes may bind to stable microtubules. We further found that upon nutrient deprivation, tubulin acetylation increases both in labile and stable microtubules and is required to allow autophagy stimulation. Tubulin hyperacetylation on lysine 40 enhances kinesin-1 and JIP-1 recruitment on microtubules and allows JNK phosphorylation and activation. JNK, in turn, triggers the release of Beclin 1 from Bcl-2-Beclin 1 complexes and its recruitment on microtubules where it may initiate autophagosome formation. Finally, although kinesin-1 functions to carry autophagosomes in basal conditions, it is not involved in motoring autophagosomes after nutrient deprivation. Our results show that the dynamics of microtubules and tubulin post-translational modifications play a major role in the regulation of starvation-induced autophagy.
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PMID:Starvation-induced hyperacetylation of tubulin is required for the stimulation of autophagy by nutrient deprivation. 2048 55

Autophagy is a spatially regulated process in axons; autophagosomes form preferentially in the distal axon tip then move actively and processively toward the cell body. Despite the primarily unidirectional transport observed in live-cell imaging experiments, both anterograde-directed KIF5/kinesin-1 motors and retrograde-directed dynein motors are tightly associated with axonal autophagosomes. Here, we discuss our recent work identifying the scaffolding protein MAPK8IP1/JIP1 (mitogen-activated protein kinase 8 interacting protein 1) as a key regulator of autophagosome transport in neurons. MAPK8IP1 tightly coordinates motor activity to ensure the fidelity of retrograde autophagosome transport in the axon.
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PMID:MAPK8IP1/JIP1 regulates the trafficking of autophagosomes in neurons. 2548 67

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