Enaptin, a giant actin-binding protein, is an element of the nuclear membrane and the actin cytoskeleton

• Published in: Experimental cell research Vol. 295; no. 2; pp. 330 - 339
• Main Authors: Padmakumar, V.C, Abraham, Sabu, Braune, Stephan, Noegel, Angelika A, Tunggal, Budi, Karakesisoglou, Iakowos, Korenbaum, Elena
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2004
• Subjects: Actinin - metabolism; Actins - metabolism; Alternative Splicing; ANC-1; Animals; Antibodies - metabolism; Base Sequence; Cell Compartmentation; Cell Line; Cell Membrane - chemistry; Cell Membrane - genetics; Cell Membrane - metabolism; Cell Nucleus - chemistry; Cercopithecus aethiops; Cloning, Molecular; COS Cells; Cytoskeleton - chemistry; Cytoskeleton - genetics; Cytoskeleton - metabolism; Green Fluorescent Proteins; Humans; Luminescent Proteins - metabolism; Mice; Microfilament Proteins - genetics; Microfilament Proteins - metabolism; Molecular Weight; Nerve Tissue Proteins; Nuance; Nuclear membrane; Nuclear Proteins; Protein Isoforms - chemistry; Protein Isoforms - genetics; Protein Structure, Tertiary; Recombinant Proteins - metabolism; Spectrin repeats; Tissue Distribution; Nuclear membrane; ANC-1; Spectrin repeats; Nuance
• ISSN: 0014-4827; 1090-2422
• DOI: 10.1016/j.yexcr.2004.01.014

Enaptin belongs to a family of recently identified giant proteins that associate with the F-actin cytoskeleton as well as the nuclear membrane. It is composed of an N-terminal alpha-actinin type actin-binding domain (ABD) followed by a long coiled coil rod and a transmembrane domain at the C-terminus. The ABD binds to F-actin in vivo and in vitro and leads to bundle formation. The human
Enaptin gene spreads over 515 kb and gives rise to several splicing isoforms (Nesprin-1, Myne-1, Syne-1, CPG2). The longest assembled cDNA encompasses 27,669 bp and predicts a 1014 kDa protein. Antibodies against the ABD of Enaptin localise the protein at F-actin-rich structures throughout the cell and in focal contacts as well as at the nuclear envelope. In COS7 cells, the protein is also present within the nuclear compartment. With the discovery of the actin-binding properties of Enaptin and the highly homologous Nuance, we define a family of proteins that integrate the cytoskeleton with the nucleoskeleton.