The tubulin molecule is a heterodimer composed of two polypeptide chains, designated alpha and beta; both alpha and beta exist in numerous isotypic forms, which differ in their assembly and drug binding properties. 2-(4-Fluorophenyl)-1-(2-chloro-3, 5-dimethoxyphenyl)-3-methyl-6-phenyl-4(1H)-pyridinone (IKP-104) is an antimitotic compound which inhibits polymerization and induces depolymerization of microtubules [Mizuhashi, F., et al. (1992) Jpn. J. Cancer Res. 83, 211]. Since the previous work was undertaken with isotypically unfractionated tubulin, we have investigated the interactions of IKP-104 with the isotypically purified tubulin dimers (alpha beta(II), alpha beta(III), and alpha beta(IV)). We find that IKP-104 binds to alpha beta(II) and alpha beta(III) at two classes of binding sites. However, affinities for each class of site are much weaker for alpha beta(III) than for alpha beta(II). Interestingly, the low-affinity site on alpha beta(IV) was not detectable. Its high-affinity site was weaker than those of either alpha beta(II) or alpha beta(III). In a pattern consistent with these results, IKP-104 inhibited assembly better with alpha beta(II) than with the other two dimers. Higher concentrations of IKP-104 induced formation of spiral aggregates from alpha beta(II) and alpha beta(III) but not from alpha beta(IV). Our results suggest that the interaction of IKP-104 with tubulin isotypes is very complex: alpha beta(II) and alpha beta(III) differ quantitatively in their interaction with IKP-104, and alpha beta(IV)'s interaction differs both quantitatively and qualitatively from those of the other two dimers.

01 Dec 1998·BiochemistryQ3 · BIOLOGY

IKP104-Induced Decay of Tubulin: Role of the A-Ring Binding Site of Colchicine

Q3 · BIOLOGY

Article

Author: Ludueña, Richard F. ; Tomita, Isao ; Potenziano, James L. ; Murata, Kyoji ; Chaudhuri, Asish R. ; Mizuhashi, Fukutaro

Tubulin, the major subunit protein of microtubules, has a tendency to lose its ability to assemble or to interact with ligands in a time-dependent process known as decay. Decay involves the increase in exposure of sulfhydryl groups and hydrophobic areas. The antimitotic drug IKP104 [2-(4-fluorophenyl)-1-(2-chloro-3, 5-dimethoxyphenyl)-3-methyl-6-phenyl-4(1H)-pyridinone] accelerates the decay of tubulin [Ludueña et al. (1995) Biochemistry 34, 15751-15759]. In the presence of colchicine, however, IKP104 stabilizes tubulin against decay. We have shown that the stability and the acceleration of the decay of tubulin are mediated respectively by the high- and low-affinity binding site(s) of IKP104 [Chaudhuri et al. (1998) J. Protein Chem. 17, 303-309]. To better understand the mechanism by which colchicine protects tubulin from IKP104-induced decay, we examined the effect of colchicine and its analogues on this process. We found that IKP104 unfolds tubulin in a process involving a specific domain where colchicine interacts, although the binding sites of these two drugs are distinctly different. 2-Methoxy-5-(2',3',4'-trimethoxyphenyl) tropolone (MTPT), the bicyclic analogue of colchicine that lacks the B-ring, can also protect tubulin from IKP104-induced decay. An A-ring analogue of colchicine, 3,4,5-trimethoxybenzaldehyde (TMB), can also stop IKP104-induced unfolding of tubulin significantly. Interestingly, the C-ring analogue of colchicine, tropolone methyl ether (TME), does not prevent this process. Our results thus suggest that neither the B-ring nor the C-ring binding regions of colchicine are involved in the IKP104-induced decay and that the A-ring binding site of colchicine on tubulin plays a crucial role in IKP104-induced decay.

01 Oct 1998·Journal of Protein Chemistry

Podophyllotoxin and nocodazole counter the effect of IKP104 on tubulin decay

Article

Author: Kyoji Murata ; Isao Tomita ; Richard F. Ludueña ; Veena Prasad ; Asish Ray Chaudhuri ; Matthew Curcio ; Fukutaro Mizuhashi

Tubulin, the subunit protein of microtubules, undergoes a time-dependent loss of functional properties known as decay. We have previously shown that the drug 2-(4-fluorophenyl)- -(2-chloro-3,5-dimethoxyphenyl)-3-methyl-6-phenyl-4(1H)-pyridinone (IKP104) accelerates decay, but that in the presence of colchicine, IKP104 becomes a stabilizer of tubulin. To see if this is due to conformational effects specific to colchicine or simply to occupancy at the colchicine site, we examined the effects of nocodazole and podophyllotoxin, two well-known competitive inhibitors of colchicine for binding to tubulin, on IKP104's acceleration of decay. We found that podophyllotoxin abolished IKP104's accelerating effect and, like colchicine, turned it into a stabilizer of tubulin. Nocodazole's effects were similar to those of podophyllotoxin and colchicine, in that it abolished IKP104-induced enhancement of decay; however, in the presence of nocodazole, IKP104 caused little or no stabilization of tubulin. Since colchicine, nocodazole, and podophyllotoxin have very different interactions with tubulin, but all inhibit the IKP104-induced enhancement of decay, our findings suggest that this inhibition arises from occupancy of the colchicine site rather than from a direct conformational effect of these two drugs.

100 Deals associated with IKP-104

R&D Status

10 top R&D records.

to view more data

Indication	Highest Phase	Country/Location	Organization	Date
Neoplasms	Preclinical	JP	Ihara Chemical Industry Co., Ltd.	-

Clinical Result

Indication

Phase

Evaluation

View All Results

Translational Medicine

Boost your research with our translational medicine data.

view full example data

Deal

Boost your decision using our deal data.

view full example data

Core Patent

Boost your research with our Core Patent data.

view full example data

Clinical Trial

Identify the latest clinical trials across global registries.

view full example data

Approval

Accelerate your research with the latest regulatory approval information.

view full example data

Regulation

Understand key drug designations in just a few clicks with Synapse.

view full example data

Chat with Hiro

Get started for free today!

Accelerate Strategic R&D decision making with Synapse, PatSnap’s AI-powered Connected Innovation Intelligence Platform Built for Life Sciences Professionals.

Start your data trial now!

Synapse data is also accessible to external entities via APIs or data packages. Empower better decisions with the latest in pharmaceutical intelligence.

Bio

Bio Sequences Search & Analysis

Chemical

Chemical Structures Search & Analysis


No Data

IKP-104

Overview

Basic Info

Structure

Related

R&D Status

Clinical Result

Translational Medicine

Deal

Core Patent

Clinical Trial

Approval

Regulation