MACF1 Background Information MACF1 (Microtubule-actin cross-linking factor 1) is a 5,327 amino acid protein that is encoded by the human gene MACF1. MACF1 belongs to the plakin or cytolinker family and contains one actin-binding domain, two CH (calponin-homology) domains, two EF-hand domains, one SH3 domain and thirty-seven spectrin repeats. MACF1 is an F-actin-binding protein which may play a role in cross-linking actin to other cytoskeletal proteins and also binds to microtubules. The spectrin repeats, an important feature found in many proteins involved in cytoskeletal structure, forms a three helix bundle with the second helix (with proline interrupts in some sequences). MACF1 is a cytoplasmic protein expressed mainly in lung, brain, spinal cord, skeletal and cardiac muscle, and skin.
