AHNAK1 and AHNAK2 are costameric proteins: AHNAK1 affects transverse skeletal muscle fiber stiffness

• Published in: Biochemical and biophysical research communications Vol. 401; no. 1; pp. 143 - 148
• Main Authors: Marg, Andreas, Haase, Hannelore, Neumann, Tanja, Kouno, Michiyoshi, Morano, Ingo
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 08.10.2010
• Subjects: 60 APPLIED LIFE SCIENCES; AHNAK1; AHNAK2; Animals; ANTIBODIES; ATOMIC FORCE MICROSCOPY; BIOLOGICAL REPAIR; Costamer; Cytoskeletal Proteins; Elastic Modulus; Fiber stiffness; FIBERS; LASERS; Male; Membrane Proteins - chemistry; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membrane repair; MICE; Mice, Inbred Strains; Microscopy, Atomic Force; Muscle Fibers, Skeletal - chemistry; Muscle Fibers, Skeletal - metabolism; MUSCLES; Neoplasm Proteins - chemistry; Neoplasm Proteins - genetics; Neoplasm Proteins - metabolism; Nuclear Pore Complex Proteins - chemistry; Nuclear Pore Complex Proteins - genetics; Nuclear Pore Complex Proteins - metabolism; PROTEINS; Skeletal muscle; WOUNDS; Fiber stiffness; FDB; AHNAK1; Costamer; AHNAK2; LSM; AFM; Membrane repair; wt; Skeletal muscle
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2010.09.030

► AHNAK1 and AHNAK2 are costameric proteins. ► Intact membrane repair in AHNAK1-deficient mice. ► AHNAK1 −/− single fibers have a higher transverse stiffness. 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.