As a component of the LINC (LInker of Nucleoskeleton and Cytoskeleton) complex, involved in the connection between the nuclear lamina and the cytoskeleton. The nucleocytoplasmic interactions established by the LINC complex play an important role in the transmission of mechanical forces across the nuclear envelope and in nuclear movement and positioning (By similarity). Behaves as a kinesin cargo, providing a functional binding site for kinesin-1 at the nuclear envelope. Hence may contribute to the establishment of secretory epithelial morphology, by promoting kinesin-dependent apical migration of the centrosome and Golgi apparatus and basal localization of the nucleus. Core component of LINC complexes which are composed of inner nuclear membrane SUN domain-containing proteins coupled to outer nuclear membrane KASH domain-containing nesprins. SUN and KASH domain-containing proteins seem to bind each other promiscuously; however, differentially expression of LINC complex constituents can give rise to specific assemblies. Probably part of a SUN1-containing LINC complex. Interacts with kinesins KIF5B and KLC1. Localization at the nucleus outer membrane location requires the presence of SUN1. Expressed in secretory epithelial cells, such as those found in exocrine pancreas, bulbourethral gland, mammary gland and salivary gland (at protein level). Also expressed in the cochlea, where it is restricted primarily to the 3 rows of outer hair cells and 1 row of inner hair cells (at protein level). Not detected in other cells of the cochlea, including Deiter's cells and pillar cells, nor in liver and kidney (at protein level). In the cochlea, low expression at P0 and P15, then rises significantly by P30 and remains steady. In the HC11 cell line model, up-regulated during differentiation of mammary cells into milk-secreting cells (at protein level). The KASH domain, which contains a transmembrane domain, mediates the nuclear envelope targeting and is involved in the binding to SUN1 and SUN2 through recognition of their SUN domains. The disulfid bond with SUN1 or SUN2 is required for stability of the respective LINC complex under tensile forces. Mice are born at the expected Mendelian rate and look overtly normal. In the cochlea, outer hair cells form, but appear to degenerate as hearing matures. Inner hair cells remain intact. Hearing loss is already detected at P15 and progresses at all frequencies by P60. Belongs to the nesprin family.