Mediates and enhances the nuclear envelope docking of RANGAP proteins mediated by WIT1 and WIT2 in the undifferentiated cells of root tips (PubMed:17600715). As component of the SUN-WIP-WIT2-KAKU1 complex, mediates the transfer of cytoplasmic forces to the nuclear envelope (NE), leading to nuclear shape changes (PubMed:25759303). Component of Ran complexes at least composed of WIT1 or WIT2, RANGAP1 or RANGAP2, and WIP1 or WIP2 or WIP3 (By similarity). Interacts with RANGAP1, WPP1/MAF1, and WPP2/MAF2 (PubMed:17600715). Interacts with SUN1 and SUN2 (PubMed:22270916). Core component of the LINC complex which is composed of inner nuclear membrane SUN domain-containing proteins coupled to outer nuclear membrane WIP and WIT proteins. The LINC complex also involves nucleoskeletal proteins CRWN/LINC and possibly KAKU4 and the cytoskeletal myosin KAKU1 (PubMed:25759303). Interacts with WIT2 (PubMed:25759303). Expressed in seedlings, roots, stems, leaves, and flowers. First observed in roots and cotyledons of young developing seedlings. Later confined to root tips and cauline leaves tips. In flowers, detected in the stamens and at the senescence region of developing siliques. The KASH domain, which contains a transmembrane domain, mediates the nuclear envelope targeting and is involved in the binding to the SUN proteins.