Proteins are synthesized by translation of mRNA. Their functions are regulated by posttranslational modifications such as phosphorylation due to change in their structure as well as the physical and chemical properties. In this review article, we introduced in our experiences that phosphorylation and de-phosphorylation of erythrocyte membrane skeletal proteins such as spectrin and protein 4.1 (4.1R) change their interactions with binding partners with modification of membrane mechanical functions.