GRIPAP1 and pancreatic insulinoma: We examined GRASP-1 expression in mouse tissues and cell lines and showed by Western blot that GRASP-1 is highly expressed throughout the central nervous system, including cortex, cerebellum, midbrain, and spinal cord, and in primary cultured hippocampal neurons but is absent in non-neuronal tissues and cell types with the exception of neuroendocrine insulinoma cells (Figure 3A).