Disease relevance of NSFL1C

• Elimination of different p47 GTPases in mice by gene targeting severely cripples IFN-gamma-regulated defence against Toxoplasma gondii, Listeria monocytogenes, Mycobacterium spp. and other pathogens [1].

High impact information on NSFL1C

• p47 is a cofactor for p97-mediated membrane fusion [2].
• Here, we report the three-dimensional cryo-electron microscopy structures at approximately 20 A resolution in two nucleotide states of the endogenous hexameric p97 in complex with a recombinant p47 trimer, one of the major p97 adaptor proteins involved in membrane fusion [3].
• The p47 SEP domain adopts a novel fold with a betabetabetaalphaalphabeta secondary structure arrangement, where beta4 pairs in a parallel fashion to beta1 [4].
• The phosphorylated p47 does not bind to Golgi membranes [5].
• The localization and phosphorylation of p47 are important for Golgi disassembly-assembly during the cell cycle [5].

Biological context of NSFL1C

• For the cell-cycle regulation of the p97/p47 pathway, it has been reported that the localization and phosphorylation-dephosphorylation of p47 are crucial [6].
• One of these p47 GTPases (Iigp1) was shown by small interfering RNA silencing experiments to specifically inhibit human strains, but not the mouse strain [7].
• With most stimuli activation of the oxidase is accompanied by multisite phosphorylation of the 47-kDa cytosolic oxidase factor (p47) which translocates from cytosol to membranes [8].
• PPARgamma-mediated down-regulation of p47 phagocyte oxidase, a component of the NAD(P)H oxidase system, was identified as one molecular mechanism causing inhibition of superoxide radical formation [9].
• Transcriptional mapping demonstrated that an early 4.2-kb RNA encoded the p47 open reading frame and probably overlapped the 39K delayed-early gene [10].

Anatomical context of NSFL1C

• In the case of p47, which is involved in the reassembly of the ER, the nuclear envelope and the Golgi apparatus, binding is mediated by a UBA domain [11].
• We previously reported that p97/p47-assisted membrane fusion is important for the reassembly of organelles at the end of mitosis, but not for their maintenance during interphase [12].
• The phagocyte NADPH oxidase system, as previously defined by cell-free reconstitution, is comprised of five essential components, three of which are produced during late phagocytic differentiation--namely, two cytosolic proteins, p47- and p67-phox--and the large subunit of cytochrome b558, gp91-phox [13].
• Phosphorylation of p47 was studied by immunoprecipitation from neutrophil cytosol and membrane fractions followed by two-dimensional gel electrophoresis and autoradiography [8].
• In contrast, the full spectrum of p47 phosphoproteins was present in the cytosol over the entire time course we studied [8].

Associations of NSFL1C with chemical compounds

• In the cytosol of phorbol myristate acetate-activated neutrophils eight distinct p47 phosphoproteins were present [8].
• Platelets adhered to the immobilized octapeptide, and anti-bodies directed against other platelet collagen receptors (glycoprotein (GP) Ia/IIa, GP IV, p65, p47) did not impair this adhesion [14].
• In the presence of 16.7 mmol/l glucose protein production of p47( phox ) was increased by 1.7-fold in isolated rat islets after 1 h, while in the presence of 0.1 mmol/l palmitic acid or 5 ng/ml IL-1beta it was increased by 1.4-fold or 1.8-fold, respectively [15].
• RESULTS: Incubation for 24 h in 0.1 mmol/l palmitic acid or a pro-inflammatory cytokine cocktail increased p47( phox ) protein production by 1.5-fold or by 1.75-fold, respectively, in the BRIN BD11 beta cell line [15].
• Both BAPTA and Ro 31-8220 prevented 5HT secretion from intact platelets; however, in Ca2+-depleted, -permeable platelets, cathepsin G was able to evoke 5HT secretion and p47 phosphorylation independently of [Ca2+]i increase, both effects being hampered by Ro 31-8220 [16].

Physical interactions of NSFL1C

• Additional recent findings suggest that ER maintenance also requires ongoing homotypic membrane fusion, possibly controlled by the p97/p47/VICP135 protein complex [17].

Other interactions of NSFL1C

• The principal role of the p97-p47 complex is in regulation of membrane fusion events [4].
• A second essential cofactor, VCIP135, was identified as a p97/p47/syntaxin5-interacting protein [6].
• The N-terminal domain of valosine-containing protein serves as an interface to its adaptor proteins p47 and Ufd1, whereas the physiologic interaction partner of the N-terminal domain of PEX1 remains unknown [18].

Analytical, diagnostic and therapeutic context of NSFL1C

• METHODS: Rat pancreatic islets or clonal rat BRIN BD11 beta cells were incubated in the presence of glucose, palmitic acid or pro-inflammatory cytokines for periods between 1 and 24 h. p47( phox ) production was determined by western blotting [15].
• Confocal microscopy demonstrated that NADPH oxidase assembly was disrupted, and LVS phagosomes did not acquire gp91/p22(phox) or p47/p67(phox) [19].
• In contrast, ligation of the CD40 receptor and autocrine signaling by TNF activate a seemingly distinct, p47 GTPase-independent mechanism leading to autophagic elimination of intracellular T. gondii, without prior disruption of the pathogen vacuole [20].

References