Abstract
This study investigates the occurrence and regulation of serine/threonine protein phosphatases (PPases) in insulin-secreting RINm5F insulinoma cells. PPases types 1 and 2A were identified in crude RINm5F cell homogenates by both enzymatic assay and Western blot analysis. We then characterized and compared the inhibitory actions of several compounds isolated from cyanobacteria, marine dinoflagellates and marine sponges, (viz. okadaic acid, microcystin-LR, calyculin-A and nodularin) cation-independent PPase activities in RINm5F cell homogenates. It was found that okadaic acid was the least potent inhibitor (IC50≈10-9M, IC100≈10-6M), while the other compounds exhibited IC50 values of ≈5·10-10 M and IC100≈ 5·10-9 M. The findings indicate that the inhibitory substances employed in this study may be used pharmacologically to investigate the role of serine/threonine PPases in RINm5F cell insulin secretion, a process that is likely to be regulated to a major extent by protein phosphorylation.
| Original language | English |
|---|---|
| Pages (from-to) | 349-358 |
| Number of pages | 10 |
| Journal | Bioscience Reports |
| Volume | 13 |
| Issue number | 6 |
| DOIs | |
| State | Published - Dec 1 1993 |
| Externally published | Yes |
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Keywords
- insulin secretion
- insulinoma
- okadaic acid
- protein phosphatase
ASJC Scopus subject areas
- Cell Biology
- Biochemistry, Genetics and Molecular Biology(all)
Cite this
Characterization of serine/threonine protein phosphatases in RINm5F insulinoma cells. / Sjöhom, Åke; Honkanen, Richard E.; Berggren, Per Olof.
In: Bioscience Reports, Vol. 13, No. 6, 01.12.1993, p. 349-358.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Characterization of serine/threonine protein phosphatases in RINm5F insulinoma cells
AU - Sjöhom, Åke
AU - Honkanen, Richard E.
AU - Berggren, Per Olof
PY - 1993/12/1
Y1 - 1993/12/1
N2 - This study investigates the occurrence and regulation of serine/threonine protein phosphatases (PPases) in insulin-secreting RINm5F insulinoma cells. PPases types 1 and 2A were identified in crude RINm5F cell homogenates by both enzymatic assay and Western blot analysis. We then characterized and compared the inhibitory actions of several compounds isolated from cyanobacteria, marine dinoflagellates and marine sponges, (viz. okadaic acid, microcystin-LR, calyculin-A and nodularin) cation-independent PPase activities in RINm5F cell homogenates. It was found that okadaic acid was the least potent inhibitor (IC50≈10-9M, IC100≈10-6M), while the other compounds exhibited IC50 values of ≈5·10-10 M and IC100≈ 5·10-9 M. The findings indicate that the inhibitory substances employed in this study may be used pharmacologically to investigate the role of serine/threonine PPases in RINm5F cell insulin secretion, a process that is likely to be regulated to a major extent by protein phosphorylation.
AB - This study investigates the occurrence and regulation of serine/threonine protein phosphatases (PPases) in insulin-secreting RINm5F insulinoma cells. PPases types 1 and 2A were identified in crude RINm5F cell homogenates by both enzymatic assay and Western blot analysis. We then characterized and compared the inhibitory actions of several compounds isolated from cyanobacteria, marine dinoflagellates and marine sponges, (viz. okadaic acid, microcystin-LR, calyculin-A and nodularin) cation-independent PPase activities in RINm5F cell homogenates. It was found that okadaic acid was the least potent inhibitor (IC50≈10-9M, IC100≈10-6M), while the other compounds exhibited IC50 values of ≈5·10-10 M and IC100≈ 5·10-9 M. The findings indicate that the inhibitory substances employed in this study may be used pharmacologically to investigate the role of serine/threonine PPases in RINm5F cell insulin secretion, a process that is likely to be regulated to a major extent by protein phosphorylation.
KW - insulin secretion
KW - insulinoma
KW - okadaic acid
KW - protein phosphatase
UR - http://www.scopus.com/inward/record.url?scp=0027787952&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0027787952&partnerID=8YFLogxK
U2 - 10.1007/BF01150479
DO - 10.1007/BF01150479
M3 - Article
VL - 13
SP - 349
EP - 358
JO - Bioscience Reports
JF - Bioscience Reports
SN - 0144-8463
IS - 6
ER -