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Immunolocalization of cytoplasmic and myelin mCalpain in transfected Schwann cells: I. effect of treatment with growth factors
Author(s) -
Neuberger Tim,
Chakrabarti Arun K.,
Russell Terry,
DeVries George H.,
Hogan Edward L.,
Banik Naren L.
Publication year - 1997
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/(sici)1097-4547(19970301)47:5<521::aid-jnr7>3.0.co;2-j
Subject(s) - calpain , calpastatin , cytoplasm , growth factor , myelin , platelet derived growth factor receptor , biology , cytosol , transfection , microbiology and biotechnology , endocrinology , medicine , chemistry , cell culture , biochemistry , enzyme , genetics , receptor , central nervous system
We have examined the effect of growth factors on the activity and localization of calpain in transfected Schwann cells (tSc). Axolemma‐enriched fraction, cAMP, or NGF showed concentration‐dependent inhibition of both μcalpain and mcalpain activity. In contrast, both acidic FGF and basic FGF stimulated μcalpain (37%) and mcalpain (58%) of tSc while PDGF‐aa and PDGF‐bb inhibited both calpain activities. The inhibitor (calpastatin) activity was approximately 90% following treatment with NGF, cAMP, PDGF‐aa, and PDGF‐bb compared to control while this activity was 40% with FGF‐treated samples. Immunofluorescence studies indicated localization of cytoplasmic calpain in the nuclear region following growth factor treatment in the cytoplasm. Growth factor treatment caused a decrease in the intensity of calpain immunoreactivity. Treatment with cAMP or FGF resulted in strong immunoreactivity of mcalpain in the nuclear region and cytoplasm compared to untreated. The growth factors did not cause translocation of calpain to the outer surface of the cell membrane. The increased immunoreactivity seen with myelin calpain antibody was greater than cytosolic antibody. The changes seen in calpain activity and immunoreactivity following treatment with growth factors suggest that these factors may regulate calpain‐calpastatin expression and translocation to the membrane for interaction with lipids for enzyme activation. © 1997 Wiley‐Liss Inc.