title: Identification of a novel p300-specific-associating protein, PRS1 (phosphoribosylpyrophosphate synthetase subunit 1).
abstract: CBP [CREB (cAMP-response-element-binding protein)-binding protein] and p300 play critical roles in transcriptional co-activation, cell differentiation, proliferation and apoptosis. Multiple transcription factors associate with CBP/p300. With the exception of the SYT oncoprotein, no proteins have been identified that specifically associate with p300, but not CBP. In the present study, we isolated a novel p300-associated protein for which no interaction with CBP was observed by GST (glutathione S-transferase) pull-down assay using Jurkat cell lysates metabolically labelled with [35S]methionine. This protein bound the KIX (kinase-inducible) domain of p300. Following resolution by two-dimensional acrylamide gel electrophoresis, we identified the KIX-domain-bound protein by MS analysis as PRS1 (phosphoribosylpyrophosphate synthetase subunit 1), a protein essential for nucleoside biosynthesis. This is the first report to demonstrate the existence of a p300 KIX-domain-specific-interacting protein that does not interact with CBP. Thus p300 may play a role in the regulation of DNA synthesis through interactions with PRS1.
authors.affiliation: Department of Viral Oncology, Institute for Virus Research, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kaida
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ariumi
authors.forename: Keiko
authors.initials: K
authors.lastname: Baba
authors.forename: Masami
authors.initials: M
authors.lastname: Matsubae
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Takao
authors.forename: Kunitada
authors.initials: K
authors.lastname: Shimotohno
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D001665:Binding Sites; D050882:CREB-Binding Protein / Q000378:metabolism; D002457:Cell Extracts; D002460:Cell Line; D005786:Gene Expression Regulation; D006801:Humans; D013058:Mass Spectrometry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012268:Ribose-Phosphate Pyrophosphokinase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D050880:p300-CBP Transcription Factors / Q000737:chemistry / Q000378:metabolism*
chemical_list: D002457:Cell Extracts; D021122:Protein Subunits; D050882:CREB-Binding Protein; D050880:p300-CBP Transcription Factors; D012268:Ribose-Phosphate Pyrophosphokinase