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Characterization of Phosphopeptide Positional Isomers on the Transcriptional Co-activator TAZ.
- Source :
-
Biochemistry [Biochemistry] 2020 Nov 03; Vol. 59 (43), pp. 4148-4154. Date of Electronic Publication: 2020 Oct 21. - Publication Year :
- 2020
-
Abstract
- The transcriptional co-activator with the PDZ binding motif (TAZ) is a critical regulator of numerous cellular processes such as cell differentiation, development, proliferation, and cell growth. Aberrant expression and activity of TAZ are also featured in many human malignancies. A hallmark of TAZ biology is its cytoplasmic retention mediated by 14-3-3 isoforms in response to phosphorylation of Ser <superscript>89</superscript> by members of the LATS family of kinases. Following the observation that TAZ is a highly phosphorylated protein even when Ser <superscript>89</superscript> is mutated, high-resolution mass spectrometry employing data-independent acquisition and ion mobility separation was conducted to elucidate additional TAZ phosphorylation sites that may play a role in regulating this critical transcriptional rheostat. Numerous phosphorylation sites on TAZ were identified, including several novel modifications. Of notable interest was the identification of positional phosphoisomers on a phosphopeptide containing Ser <superscript>89</superscript> . Optimized use of a so-called wideband enhancement acquisition technique yielded higher-quality fragmentation data that confirmed the detection of Ser <superscript>93</superscript> as the positional phosphoisomer partner of Ser <superscript>89</superscript> and identified diagnostic fragment ions for the phosphorylation events. Functional analysis indicated that Ser <superscript>93</superscript> phosphorylation reduces the level of 14-3-3 association and increases the level of nuclear translocation, indicating this phosphorylation event attenuates the 14-3-3-mediated TAZ cytoplasmic retention mechanism. These findings suggest that the biological activities of TAZ are likely dynamically regulated by multisite phosphorylation.
- Subjects :
- 14-3-3 Proteins metabolism
Cell Differentiation drug effects
Cell Nucleus drug effects
Cell Nucleus metabolism
Cell Proliferation drug effects
Cytoplasm drug effects
Cytoplasm metabolism
HEK293 Cells
Humans
Intracellular Signaling Peptides and Proteins chemistry
Intracellular Signaling Peptides and Proteins metabolism
Phosphopeptides pharmacology
Phosphorylation
Signal Transduction physiology
Trans-Activators metabolism
Phosphopeptides chemistry
Transcription Factors chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1520-4995
- Volume :
- 59
- Issue :
- 43
- Database :
- MEDLINE
- Journal :
- Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 33086783
- Full Text :
- https://doi.org/10.1021/acs.biochem.0c00521