Involved in inflorescence stems gravitropism, by modulating vacuolar membrane (VMs) dynamics in gravity-sensing cells (e.g. endodermal cells) during the amyloplast sedimentation process. Expressed in roots (e.g. root cap of primary roots and vascular tissues), hypocotyls, cotyledons (including in guard cells), stems (e.g. epidermis, endodermis, phloem, developing metaxylem and interfascicular cells). Abnormal inflorescence stems gravitropism but normal hypocotyl gravitropism. Impaired flexible and dynamic structure of vacuolar membrane (VMs) leading to altered amyloplast sedimentation. Truncated N-terminus. Truncated N-terminus.