A switch of other TM isoforms to TM5 or TM5b and/or an increase of tropomodulin would favor the formation of actin protofilaments.

The tropomodulin-TM complex is able to bind to the pointed end of a long actin filament but not along it. The more tropomodulin bind to the N-terminal of homodimer or heterodimer of TM5 and TM5b (approximately 33-35 nm in length), the less the head-to-tail association of TM molecules can occur along the actin filaments. Increasing TM5, TM5b, and/or tropomodulin, therefore, would favor the stabilization of shorter actin filaments that are of the same size as an LMW TM molecule.