Subclass-Specific Localization and Trafficking of Arabidopsis p24 Proteins in the ER-Golgi Interface

Epithelial organs are the first barrier against microorganisms and genotoxic stress, in which the p53 family members p63 and p73 have both overlapping and distinct functions. Intriguingly, p73 displays a very specific localization to basal epithelial cells in human tissues, while p63 is expressed in both basal and differentiated cells. Here, we analyse systematically the literature describing p63 and p73 protein–protein interactions to reveal distinct functions underlying the aforementioned distribution. We have found that p73 and p63 cooperate in the genome stability surveillance in proliferating cells; p73 specific interactors contribute to the transcriptional repression, anaphase promoting complex and spindle assembly checkpoint, whereas p63 specific interactors play roles in the regulation of mRNA processing and splicing in both proliferating and differentiated cells. Our analysis reveals the diversification of the RNA and DNA specific functions within the p53 family.

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Synapsin I (protein I), a nerve terminal-specific phosphoprotein. I. Its general distribution in synapses of the central and peripheral nervous system demonstrated by immunofluorescence in frozen and plastic sections.

The Journal of Cell Biology ◽

10.1083/jcb.96.5.1337 ◽

1983 ◽

Vol 96 (5) ◽

pp. 1337-1354 ◽

Cited By ~ 345

Author(s):

P De Camilli ◽

R Cameron ◽

P Greengard

Keyword(s):

Nervous System ◽

Detailed Examination ◽

Specific Protein ◽

Nerve Cells ◽

General Distribution ◽

Synapsin I ◽

Nervous Systems ◽

Synaptic Region ◽

Specific Localization ◽

Peripheral Nervous Systems

Synapsin I (formerly referred to as protein I) is the collective name for two almost identical phosphoproteins, synapsin Ia and synapsin Ib (protein Ia and protein Ib), present in the nervous system. Synapsin I has previously been shown by immunoperoxidase studies (De Camilli, P., T. Ueda, F. E. Bloom, E. Battenberg, and P. Greengard, 1979, Proc. Natl. Acad. Sci. USA, 76:5977-5981; Bloom, F. E., T. Ueda, E. Battenberg, and P. Greengard, 1979, Proc. Natl. Acad. Sci. USA 76:5982-5986) to be a neuron-specific protein, present in both the central and peripheral nervous systems and concentrated in the synaptic region of nerve cells. In those preliminary studies, the occurrence of synapsin I could be demonstrated in only a portion of synapses. We have now carried out a detailed examination of the distribution of synapsin I immunoreactivity in the central and peripheral nervous systems. In this study we have attempted to maximize the level of resolution of immunohistochemical light microscopy images in order to estimate the proportion of immunoreactive synapses and to establish their precise distribution. Optimal results were obtained by the use of immunofluorescence in semithin sections (approximately 1 micron) prepared from Epon-embedded nonosmicated tissues after the Epon had been removed. Our results confirm the previous observations on the specific localization of synapsin I in nerve cells and synapses. In addition, the results strongly suggest that, with a few possible exceptions involving highly specialized neurons, all synapses contain synapsin I. Finally, immunocytochemical experiments indicate that synapsin I appearance in the various regions of the developing nervous system correlates topographically and temporally with the appearance of synapses. In two accompanying papers (De Camilli, P., S. M. Harris, Jr., W. B. Huttner, and P. Greengard, and Huttner, W. B., W. Schiebler, P. Greengard, and P. De Camilli, 1983, J. Cell Biol. 96:1355-1373 and 1374-1388, respectively), evidence is presented that synapsin I is specifically associated with synaptic vesicles in nerve endings.

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2SB01 Specific localization of inwardly rectifying K+ channels and its molecular basis in the vectorial transport of epithelial and glial cells

Seibutsu Butsuri ◽

10.2142/biophys.44.s14_3 ◽

2004 ◽

Vol 44 (supplement) ◽

pp. S14

Author(s):

H. Hibino ◽

Y. Kurachi

Keyword(s):

Glial Cells ◽

Molecular Basis ◽

K Channels ◽

Specific Localization ◽

Inwardly Rectifying ◽

Vectorial Transport

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Identification and Specific Localization of Tyrosine-Phosphorylated Proteins in Trypanosoma brucei

Eukaryotic Cell ◽

10.1128/ec.00366-08 ◽

2009 ◽

Vol 8 (4) ◽

pp. 617-626 ◽

Cited By ~ 27

Author(s):

Isabelle R. E. Nett ◽

Lindsay Davidson ◽

Douglas Lamont ◽

Michael A. J. Ferguson

Keyword(s):

Trypanosoma Brucei ◽

Tyrosine Kinases ◽

Immunofluorescence Microscopy ◽

Significant Proportion ◽

Tyrosine Residues ◽

Phosphorylated Proteins ◽

Cell Extracts ◽

Proteomics Approach ◽

Specific Localization ◽

Multicellular Organisms

ABSTRACT Phosphorylation on tyrosine residues is a key signal transduction mechanism known to regulate intercellular and intracellular communication in multicellular organisms. Despite the lack of conventional tyrosine kinases in the genome of the single cell organism Trypanosoma brucei, phosphorylation on trypanosomal protein tyrosine residues has been reported for this parasite. However, the identities of most of the tyrosine-phosphorylated proteins and their precise site(s) of phosphorylation were unknown. Here, we have applied a phosphotyrosine-specific proteomics approach to identify 34 phosphotyrosine-containing proteins from whole-cell extracts of procyclic form T. brucei. A significant proportion of the phosphotyrosine-containing proteins identified in this study were protein kinases of the CMGC kinase group as well as some proteins of unknown function and proteins involved in energy metabolism, protein synthesis, and RNA metabolism. Interestingly, immunofluorescence microscopy using anti-phosphotyrosine antibodies suggests that there is a concentration of tyrosine-phosphorylated proteins associated with cytoskeletal structures (basal body and flagellum) and in the nucleolus of the parasite. This localization of tyrosine-phosphorylated proteins supports the idea that the function of signaling molecules is controlled by their precise location in T. brucei, a principle well known from higher eukaryotes.

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