We report here the cloning of the murine cDNA encoding caveolin, a known v-Src substrate and caveolar marker protein. Interestingly, analysis of the murine cDNA and comparison with caveolin from other species reveals a previously unrecognized consensus site for protein kinase C (PKC) phosphorylation. This finding could have important implications as (i) both the morphology and function of caveolae are dramatically affected by PKC activators; and (ii) PKC alpha is concentrated in isolated caveolin-rich membrane domains. In addition, this first step should facilitate the use of the mouse as a genetic system for elucidating the role of caveolin in caveolar functioning.