Comparative Proteomic Analysis of Differentially Expressed Proteins between Peripheral Sensory and Motor Nerves

Peripheral sensory and motor nerves have different functions
and
different approaches to regeneration, especially their distinct ability
to accurately reinervate terminal nerve pathways. To understand the
molecular aspects underlying these differences, the proteomics technique
by coupling isobaric tags for relative and absolute quantitation (iTRAQ)
with online two-dimensional liquid chromatography tandem mass spectrometry
(2D LC-MS/MS) was used to investigate the protein profile of sensory
and motor nerve samples from rats. A total of 1472 proteins were identified
in either sensory or motor nerve. Of them, 100 proteins showed differential
expressions between both nerves, and some of them were validated by
quantitative real time RT-PCR, Western blot analysis, and immunohistochemistry.
In the light of functional categorization, the differentially expressed
proteins in sensory and motor nerves, belonging to a broad range of
classes, were related to a diverse array of biological functions,
which included cell adhesion, cytoskeleton, neuronal plasticity, neurotrophic
activity, calcium-binding, signal transduction, transport, enzyme
catalysis, lipid metabolism, DNA-binding, synaptosome function, actin-binding,
ATP-binding, extracellular matrix, and commitment to other lineages.
The relatively higher expressed proteins in either sensory or motor
nerve were tentatively discussed in combination with their specific
molecular characteristics. It is anticipated that the database generated
in this study will provide a solid foundation for further comprehensive
investigation of functional differences between sensory and motor
nerves, including the specificity of their regeneration.