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Synthesis of phosphatidylserine by base exchange in Triton‐insoluble floating fractions from rat cerebellum
Author(s) -
Buratta Sandra,
Felicetti Michela,
Mozzi Rita
Publication year - 2007
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.2007.04783.x
Subject(s) - phosphatidylserine , protein kinase c , serine , lipid raft , membrane , biochemistry , signal transduction , threonine , ethanolamine , chemistry , microbiology and biotechnology , phosphorylation , enzyme , biophysics , biology , phospholipid
Phosphatidylserine (PS), which is synthesized in mammalian tissues by the exchange between free serine and the nitrogen bases present in membrane glycerophospholipids, is strictly required for protein kinase C (PKC) activity. PKC, as other molecules involved in signal transduction, is present in lipid rafts, considered as a platform for molecular signaling. Membrane microdomains enriched in components of rafts can be isolated on the basis of their insolubility in Triton X‐100 at 4°C and their low density in sucrose density gradient. This study demonstrates the existence of serine base exchange enzyme (SBEE) in Triton‐insoluble floating fractions containing associated PKC. Using two fractions of detergent‐resistant membranes from rat cerebellum, we observed a correlation between the level of SBEE activity and that of membrane‐associated PKC. This suggests that SBEE, synthesizing PS in the binding area for PKC, participates to signal transduction. The capability of SBEE to utilize not only serine but also ethanolamine, as free exchanging base, suggests a mechanism for modulating in loco PS concentration.