title: UCS15A, a novel small molecule, SH3 domain-mediated protein-protein interaction blocking drug.
abstract: Protein-protein interactions play critical regulatory roles in mediating signal transduction. Previous studies have identified an unconventional, small-molecule, Src signal transduction inhibitor, UCS15A. UCS15A differed from conventional Src-inhibitors in that it did not alter the levels or the tyrosine kinase activity of Src. Our studies suggested that UCS15A exerted its Src-inhibitory effects by a novel mechanism that involved the disruption of protein-protein interactions mediated by Src. In the present study we have examined the ability of UCS15A to disrupt the interaction of Src-SH3 with Sam68, both in vivo and in vitro. This ability of UCS15A was not restricted to Src-SH3 mediated protein-protein interactions, since the drug was capable of disrupting the in vivo interactions of Sam68 with other SH3 domain containing proteins such as Grb2 and PLCgamma. In addition, UCS15A was capable of disrupting other typical SH3-mediated protein-protein interactions such as Grb2-Sos1, cortactin-ZO1, as well as atypical SH3-mediated protein-protein interactions such as Grb2-Gab1. However, UCS15A was unable to disrupt the non-SH3-mediated protein-protein interactions of beta-catenin, with E-cadherin and alpha-catenin. In addition, UCS15A had no effect on the SH2-mediated interaction between Grb2 and activated Epidermal Growth Factor receptor. Thus, the ability of UCS15A, to disrupt protein-protein interactions appeared to be restricted to SH3-mediated protein-protein interactions. In this regard, UCS15A represents the first example of a non-peptide, small molecule agent capable of disrupting SH3-mediated protein-protein interactions. In vitro analyses suggested that UCS15A did not bind to the SH3 domain itself but rather may interact directly with the target proline-rich domains.
authors.affiliation: Tokyo Research Laboratories, Kyowa Hakko Kogyo Co., Ltd 3-6-6 Asahi-cho, Machida-shi, Tokyo 194, Japan.
authors.forename: Chitose
authors.initials: C
authors.lastname: Oneyama
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Nakano
authors.forename: Sreenath V
authors.initials: SV
authors.lastname: Sharma
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D001547:Benzaldehydes / Q000494:pharmacology*; D000081247:CSK Tyrosine-Protein Kinase; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D051356:Cortactin; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000378:metabolism; D051380:GRB2 Adaptor Protein; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D008840:Microfilament Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D051966:Phospholipase C gamma; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D011506:Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D020837:SOS1 Protein / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D015534:Trans-Activators; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D062826:Zonula Occludens-1 Protein; D051178:alpha Catenin; D051176:beta Catenin; D018909:src Homology Domains; D019061:src-Family Kinases
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D001547:Benzaldehydes; C495273:CTNNA1 protein, human; C495270:CTNNB1 protein, human; C495868:CTTN protein, human; D015820:Cadherins; D051356:Cortactin; D003598:Cytoskeletal Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; C098587:GAB1 protein, human; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D007527:Isoenzymes; C489559:KHDRBS1 protein, human; D008565:Membrane Proteins; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011506:Proteins; D016601:RNA-Binding Proteins; D020837:SOS1 Protein; C569042:TJP1 protein, human; D015534:Trans-Activators; C426883:UCS15A; D062826:Zonula Occludens-1 Protein; D051178:alpha Catenin; D051176:beta Catenin; D004815:Epidermal Growth Factor; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human; D010738:Type C Phospholipases; D051966:Phospholipase C gamma