title: AHNAK1 and AHNAK2 are costameric proteins: AHNAK1 affects transverse skeletal muscle fiber stiffness.
abstract: The AHNAK scaffold PDZ-protein family is implicated in various cellular processes including membrane repair; however, AHNAK function and subcellular localization in skeletal muscle are unclear. We used specific AHNAK1 and AHNAK2 antibodies to analyzed the detailed localization of both proteins in mouse skeletal muscle. Co-localization of AHNAK1 and AHNAK2 with vinculin clearly demonstrates that both proteins are components of the costameric network. In contrast, no AHNAK expression was detected in the T-tubule system. A laser wounding assay with AHNAK1-deficient fibers suggests that AHNAK1 is not involved in membrane repair. Using atomic force microscopy (AFM), we observed a significantly higher transverse stiffness of AHNAK1⁻/⁻ fibers. These findings suggest novel functions of AHNAK proteins in skeletal muscle.
authors.affiliation: Max-Delbrück-Centrum für Molekulare Medizin, D-13092 Berlin, Germany. andreas.marg@mdc-berlin.de
authors.forename: Andreas
authors.initials: A
authors.lastname: Marg
authors.forename: Hannelore
authors.initials: H
authors.lastname: Haase
authors.forename: Tanja
authors.initials: T
authors.lastname: Neumann
authors.forename: Michiyoshi
authors.initials: M
authors.lastname: Kouno
authors.forename: Ingo
authors.initials: I
authors.lastname: Morano
mesh_terms: D000818:Animals; D003598:Cytoskeletal Proteins; D055119:Elastic Modulus; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D018625:Microscopy, Atomic Force; D018485:Muscle Fibers, Skeletal / Q000737:chemistry* / Q000378:metabolism; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: C489572:Ahnak protein, mouse; C553746:Ahnak2 protein, mouse; D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D028861:Nuclear Pore Complex Proteins