[Alpha-actinin sites on microvilli of the rabbit small intestine demonstrated by immunoperoxidase].

When Mooseker and Tilney showed the microvilli system must be ascribed among non-muscle contractile systems, they have proposed a contractile scheme formed by actin, miosin and probably alpha-actinin. The scheme proposed by these AA. consists of actin filaments oriented and running from the border to the base, bound to the border by a plate of dense substance formed by -actinin and, to the base, other perpendicular miosin filaments. In our opinion, Mooseker and Tilney research lacks a demonstration regarding alpha-actinin and that is reason why we have decided to display this protein in the microvilli by immunoperoxidase techniques. Considering our results we can definitively confirm the full validity of the contractile scheme of Mooseker and Tilney.