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Protein phosphorylation in the blood-brain barrier. Possible presence of MARCKS in brain microvessels
R Edgardo Catalán1, A M Martínez, M Dolores Aragonés
1Departamento de Biología Molecular, Universidad Autónoma de Madrid, Spain.
Abstract:
The protein phosphorylation in rat brain microvessels has been examined; the major phosphorylated proteins correspond to a doublet of molecular weight 134-141 kDa, and four proteins of approx. 25, 55, 80 and 200 kDa. TPA (12-O-tetradecanoylphorbol-13-acetate) enhanced, in a few minutes, the phosphorylation of three major protein substrates with apparent molecular weights of 17.5, 44.5 and 80 kDa. These effects are inhibited by staurosporine. The 80 kDa protein resulted to be myristoylated alanine-rich C kinase substrate (MARCKS). This work demonstrates that protein kinase C plays an important role in protein phosphorylation in blood-brain barrier (BBB).
Insights
Protein kinase C significantly impacts protein phosphorylation within rat brain microvessels, particularly affecting the blood-brain barrier (BBB). This study identifies key phosphorylated proteins and how TPA influences their phosphorylation.
Area of Science:
- Neuroscience
- Biochemistry
- Cell Biology
Background:
- Protein phosphorylation is crucial for cellular signaling and function in the brain.
- The blood-brain barrier (BBB) regulates the passage of substances into the central nervous system, and its protein components are vital for its integrity.
Purpose of the Study:
- To investigate protein phosphorylation patterns in rat brain microvessels.
- To determine the role of protein kinase C (PKC) in regulating protein phosphorylation within the BBB.
- To identify specific protein substrates affected by PKC activation.
Main Methods:
- Analysis of protein phosphorylation in isolated rat brain microvessels.
- Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) to activate PKC.
- Inhibition studies using staurosporine.
- Identification of phosphorylated proteins using molecular weight markers.
- Characterization of the 80 kDa protein substrate as myristoylated alanine-rich C kinase substrate (MARCKS).
Main Results:
- Identified major phosphorylated proteins in rat brain microvessels, including a doublet at 134-141 kDa and proteins at approximately 25, 55, 80, and 200 kDa.
- TPA rapidly enhanced the phosphorylation of three major substrates (17.5, 44.5, and 80 kDa).
- Staurosporine, a PKC inhibitor, blocked these TPA-induced phosphorylation effects.
- The 80 kDa phosphoprotein was identified as MARCKS.
Conclusions:
- Protein kinase C plays a significant role in the regulation of protein phosphorylation in the rat blood-brain barrier.
- MARCKS is a key substrate for PKC in brain microvessels.
- These findings provide insights into the molecular mechanisms governing BBB function and signaling.