Acts upstream of or within several processes, including negative regulation of osteoblast differentiation; substrate adhesion-dependent cell spreading; and type II pneumocyte differentiation. Located in endoplasmic reticulum. Is expressed in several structures, including adipose tissue; alimentary system; genitourinary system; nervous system; and respiratory system. Orthologous to human FNDC3B (fibronectin type III domain containing 3B). [provided by Alliance of Genome Resources, Apr 2022]