Abstract
The bryostatins represent a unique class of activators of protein kinase C (PKC) which induce only a subset of the responses typical of the phorbol esters and block those responses to the phorbol esters which they themselves do not induce. To better understand the interaction of the bryostatins with PKC, we have synthesized [26-3H]byrostatin 4 and characterized its binding to PKC. [3H]Bryostatin 4 and [3H]phorbol 12,13-dibutyrate ([3H]PDBu) differed markedly in their binding to PKC reconstituted with phosphatidylserine (PS). The binding affinity of [3H]bryostatin 4 under these conditions was too high to measure and the rate of release of bound bryostatin was much slower than that of the phorbol esters, with a half-time of several hours. These properties caused bryostatin 1 to appear to inhibit [3H]PDBu binding under these conditions in a non-competitive fashion. Both the high potency and the slow rate of release of the bryostatins may contribute to their unique pattern of biological activity. By reconstituting PKC in a mixture of 1.5% Triton X-100:0.3% PS, we were able to establish reversible conditions for [3H]bryostatin 4 binding. Under these conditions, binding of [3H]bryostatin 4 was competitively inhibited by PDBu, consistent with both the bryostatin and phorbol esters binding to PKC in a qualitatively similar fashion. Binding affinities to PKC isozymes α, β, and γ were compared and little difference was found, suggesting that differential recognition by these isozymes does not account for the unique biological activity of the bryostatins.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 2007-2014 |
| Number of pages | 8 |
| Journal | Biochemical Pharmacology |
| Volume | 43 |
| Issue number | 9 |
| DOIs | |
| State | Published - May 8 1992 |
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ASJC Scopus subject areas
- Pharmacology
Cite this
Binding of [3H]bryostatin 4 to protein kinase C. / Lewin, Nancy E.; Dell'Aquila, Marie L.; Pettit, George; Blumberg, Peter M.; Warren, Barbour S.
In: Biochemical Pharmacology, Vol. 43, No. 9, 08.05.1992, p. 2007-2014.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Binding of [3H]bryostatin 4 to protein kinase C
AU - Lewin, Nancy E.
AU - Dell'Aquila, Marie L.
AU - Pettit, George
AU - Blumberg, Peter M.
AU - Warren, Barbour S.
PY - 1992/5/8
Y1 - 1992/5/8
N2 - The bryostatins represent a unique class of activators of protein kinase C (PKC) which induce only a subset of the responses typical of the phorbol esters and block those responses to the phorbol esters which they themselves do not induce. To better understand the interaction of the bryostatins with PKC, we have synthesized [26-3H]byrostatin 4 and characterized its binding to PKC. [3H]Bryostatin 4 and [3H]phorbol 12,13-dibutyrate ([3H]PDBu) differed markedly in their binding to PKC reconstituted with phosphatidylserine (PS). The binding affinity of [3H]bryostatin 4 under these conditions was too high to measure and the rate of release of bound bryostatin was much slower than that of the phorbol esters, with a half-time of several hours. These properties caused bryostatin 1 to appear to inhibit [3H]PDBu binding under these conditions in a non-competitive fashion. Both the high potency and the slow rate of release of the bryostatins may contribute to their unique pattern of biological activity. By reconstituting PKC in a mixture of 1.5% Triton X-100:0.3% PS, we were able to establish reversible conditions for [3H]bryostatin 4 binding. Under these conditions, binding of [3H]bryostatin 4 was competitively inhibited by PDBu, consistent with both the bryostatin and phorbol esters binding to PKC in a qualitatively similar fashion. Binding affinities to PKC isozymes α, β, and γ were compared and little difference was found, suggesting that differential recognition by these isozymes does not account for the unique biological activity of the bryostatins.
AB - The bryostatins represent a unique class of activators of protein kinase C (PKC) which induce only a subset of the responses typical of the phorbol esters and block those responses to the phorbol esters which they themselves do not induce. To better understand the interaction of the bryostatins with PKC, we have synthesized [26-3H]byrostatin 4 and characterized its binding to PKC. [3H]Bryostatin 4 and [3H]phorbol 12,13-dibutyrate ([3H]PDBu) differed markedly in their binding to PKC reconstituted with phosphatidylserine (PS). The binding affinity of [3H]bryostatin 4 under these conditions was too high to measure and the rate of release of bound bryostatin was much slower than that of the phorbol esters, with a half-time of several hours. These properties caused bryostatin 1 to appear to inhibit [3H]PDBu binding under these conditions in a non-competitive fashion. Both the high potency and the slow rate of release of the bryostatins may contribute to their unique pattern of biological activity. By reconstituting PKC in a mixture of 1.5% Triton X-100:0.3% PS, we were able to establish reversible conditions for [3H]bryostatin 4 binding. Under these conditions, binding of [3H]bryostatin 4 was competitively inhibited by PDBu, consistent with both the bryostatin and phorbol esters binding to PKC in a qualitatively similar fashion. Binding affinities to PKC isozymes α, β, and γ were compared and little difference was found, suggesting that differential recognition by these isozymes does not account for the unique biological activity of the bryostatins.
UR - http://www.scopus.com/inward/record.url?scp=0026612631&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0026612631&partnerID=8YFLogxK
U2 - 10.1016/0006-2952(92)90644-X
DO - 10.1016/0006-2952(92)90644-X
M3 - Article
C2 - 1596288
AN - SCOPUS:0026612631
VL - 43
SP - 2007
EP - 2014
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
SN - 0006-2952
IS - 9
ER -