Types of cells that depend on movement of ions across the cell membrane, have high metabolic capacity, or must communicate with other cells in some way, would tend to have a higher concentration of proteins in their membranes. This would apply to the membranes in their organelles as well as the cell membrane.
Proteins are the primary mechanism for moving all but lipid soluble compounds across the membrane.
They also make up the electron transport chain and ATP synthase proteins of the inner mitochondrial membrane. Neurons also have many receptor proteins for receiving chemical information from other neurons. So in short, nerve cells would have a relatively high concentration of proteins, but if myelinated, would have a higher concentration of lipids overall. Mitochondria would have lots of transporter proteins and electron transport proteins, making the overall composition high in protein, low in phospholipid content. Therefore, the inside of the artificial cell is hypertonic relative to the outside.