Protein kinase C-alpha (PKC alpha) has been studied widely as a paradigm for conventional PKCs, with two C1 domains (C1A and C1B) being important for the regulation and function of the kinase. However, it is challenging to explore these domains in membrane-bound environments with either simulations or experiments alone. In this work, we have combined modeling, simulations, and experiments to understand the molecular basis of the PKC alpha C1A and C1B domain interactions with membranes. Our atomistic simulations of the PKC alpha Cl domains reveal the dynamic interactions of the proteins with anionic lipids, as well as the conserved hydrogen bonds and the distinct nonpolar contacts formed with lipid activators. Corroborating evidence is obtained from additional simulations and experiments in terms of lipid binding and protein diffusion. Overall, our study, for the first time, explains with atomistic detail how the PKC alpha C1A and C1B domains interact differently with various lipids. On the molecular level, the information provided by our study helps to shed light on PKC alpha regulation and activation mechanism. The combined computational/experimental approach demonstrated in this work is anticipated to enable further studies to explore the roles of C1 domains in many signaling proteins and to better understand their molecular mechanisms in normal cellular function and disease development.