Pincher, a pinocytic chaperone for nerve growth factor/TrkA signaling endosomes

Abstract

Acentral tenet of nerve growth factor (NGF) action that is poorly understood is its ability to mediate cytoplasmic signaling, through its receptor TrkA, that is initiated at the nerve terminal and conveyed to the soma. We identified an NGF-induced protein that we termed Pincher (pinocytic chaperone) that mediates endocytosis and trafficking of NGF and its receptor TrkA. In PC12 cells, overexpression of Pincher dramatically stimulated NGF-induced endocytosis of TrkA, unexpectedly at sites of clathrin-independent macropinocytosis within cell surface ruffles. Subsequently, a system of Pincher-containing tubules mediated the delivery of NGF/TrkA-containing vesicles to cytoplasmic accumulations. These vesicles selectively and persistently mediated TrkA-erk5 mitogen-activated protein kinase signaling. A dominant inhibitory mutant form of Pincher inhibited the NGF-induced endocytosis of TrkA, and selectively blocked TrkA-mediated cytoplasmic signaling of erk5, but not erk1/2, kinases. Our results indicate that Pincher mediates pinocytic endocytosis of functionally specialized NGF/TrkA endosomes with persistent signaling potential.

EHD2 and the Novel EH Domain Binding Protein EHBP1 Couple Endocytosis to the Actin Cytoskeleton

“…The bottom panel in F represents high magnification of the squared area in E and shows EHD2 (arrows) and GLUT4 (arrowhead) colocalization. endocytosis and trafficking of the nerve growth factor receptor TrkA in PC12 cells has also been reported recently (36). Thus, these recent reports combined with the findings in Fig.…”

Directing traffic in neural cells: determinants of receptor tyrosine kinase localization and cellular responses

“…Over-expression of pincher in PC12 cells stimulates NGF-mediated TrkA endocytosis, whereas expression of a dominant-negative pincher inhibits TrkA internalization (Shao et al 2002). Furthermore, this mutant selectively inhibits ERK5 but not ERK1/2 phosphorylation (Shao et al 2002). The results of this study suggest that pincher-mediated trafficking regulates the selective activation of ERK pathways through TrkA.…”

“…Although gaps remain in understanding precisely how GIPC regulates RTKs, this receptor-interacting protein has emerged as an interesting target for investigation of RTK trafficking, the regulation of signal transduction and resultant cellular responses. Shao et al (2002) identified pincher (pinocytic chaperone) as a mediator of endocytosis and trafficking of NGF and its receptor TrkA. Over-expression of pincher in PC12 cells stimulates NGF-mediated TrkA endocytosis, whereas expression of a dominant-negative pincher inhibits TrkA internalization (Shao et al 2002).…”

“…Shao et al (2002) identified pincher (pinocytic chaperone) as a mediator of endocytosis and trafficking of NGF and its receptor TrkA. Over-expression of pincher in PC12 cells stimulates NGF-mediated TrkA endocytosis, whereas expression of a dominant-negative pincher inhibits TrkA internalization (Shao et al 2002). Furthermore, this mutant selectively inhibits ERK5 but not ERK1/2 phosphorylation (Shao et al 2002).…”

Association of the Atypical Protein Kinase C-interacting Protein p62/ZIP with Nerve Growth Factor Receptor TrkA Regulates Receptor Trafficking and Erk5 Signaling

“…9). It is interesting to note that a newly isolated protein, Pincher (36), has been shown to participate in clathrinindependent internalization. A dominant-negative mutant form of Pincher inhibited NGF-induced endocytosis of TrkA and selectively blocked TrkA-mediated signaling of Erk5 but not Erk1/2 kinases.…”