Interactions between peripherin and neurofilaments in cultured cells: disruption of peripherin assembly by the NF-M and NF-H subunits

Neurofilaments are the principal intermediate filament type expressed by ne urons. They are formed by the co-assembly of three subunits: NF-L, NF-M, an d NF-H. Peripherin is another intermediate filament protein expressed mostl y in neurons of the peripheral nervous system. In contrast to neurofilament s, peripherin can self-assemble to establish an intermediate filament netwo rk in cultured cells. The co-expression of neurofilaments and peripherin is found mainly during development and regeneration. We used SW13 cells devoi d of endogenous cytoplasmic intermediate filaments to assess the exact asse mbly characteristics of peripherin with each neurofilament subunit. Our res ults demonstrate that peripherin can assemble with NF-L. In contrast, the c o-expression of peripherin with the large neurofilament subunits interferes with peripherin assembly. These results confirm the existence of interacti ons between peripherin and neurofilaments in physiological conditions. More over, they suggest that perturbations in the stoichiometry of neurofilament s can have an impact on peripherin assembly in vivo.