CacyBP/SIP in the rat spinal cord in norm and after transection - Influence on the phosphorylation state of ERK1/2 and p38 kinases

Abstract

Introduction: CacyBP/SIP is a multifunctional protein present in various mammalian tissues, among them in brain. Recently, it has been shown that CacyBP/SIP exhibits phosphatase activity towards ERK1/2 and p38 kinases.

Objectives: The aim of our study was to analyze the localization and level of CacyBP/SIP and its substrates, phosphorylated ERK1/2 (p-ERK1/2) and phosphorylated p38 (p-p38) kinases, in an intact and transected rat spinal cord.

Methods: To achieve our goals we have performed Western blot/densitometric analysis and double immunofluorescence staining using rat spinal cord tissue, intact and after total transection at different time points.

Results: We have observed a decrease in the level of CacyBP/SIP and an increase in the level of p-ERK1/2 and of p-p38 in fragments of the spinal cord excised 1 and 3 months after transection. Moreover, immunofluorescence staining has shown that CacyBP/SIP, p-ERK1/2 or p-p38 co-localized with a neuronal marker, NeuN, and with an oligodendrocyte marker, Olig2.

Conclusion: The inverse correlation between CacyBP/SIP and p-ERK1/2 or p-p38 levels suggests that CacyBP/SIP may dephosphorylate p-ERK1/2 and p-p38 kinases and be involved in neural plasticity following spinal cord injury.

Keywords: CacyBP/SIP; ERK1/2 kinase; Spinal cord injury; p38 kinase.