Cell membranes are two-dimensional liquid structures that protect the cell and organelles within those cells. The cell membranes are responsible for maintaining an electrical and chemical gradient and participates in processes related to cell growth, signal transduction, and immune surveillance. A variety of membrane functions are possible due to the presence of proteins that their functional activity is influenced by factors temperature, pH, membrane potential, the presence of allosteric effectors or by the lipid composition. Membranes with different lipid compositions vary in thickness, packing, curvature, fluidity and phase transition temperature. Because proteins and lipids vary in length of hydrophobic domains, a so-called 'hydrophobic mismatch' occurs whenever these two lengths differ significantly. As a result of hydrophobic mismatch some proteins aggregate or change orientation in the membrane, others preferentially migrate to the appropriate domain, which is a postulated factor affecting protein sorting in Golgi. Similarly, lipid packing is strongly affected by lipid composition and, in particular, the presence of sterols. The varied lipid composition leads to the formation of domains that are not miscible with each other. To ensure proper functioning in the membrane, proteins tend to selectively localize in one of the domains. Experimental and computer studies using biologically active proteins have been conducted for years to determine the effect of hydrophobic mismatch and lipid packing on protein association and partitioning between microdomains. In addition, simple model WALP proteins were designed to facilitate research into phenomena related to hydrophobic mismatch. However, the presence of specific protein-membrane interactions that result from the presence of the amino acid sequence of the protein should be considered in all studies to date. The goal of our project is to elucidate how hydrophobic mismatch and lipid packing affect the association of proteins and partitioning between membrane domains independently of each other using molecular dynamics simulations. The simplified model of the transmembrane helix that we propose excludes the presence of specific interactions with lipids. We expect that the result of our research will be a simple relationship, how membrane thickness and lipid packing affect protein association and partition between membrane microdomains.