Tex2, an SMP domain-containing lipid transfer protein conserved in metazoan and yeast, is also known as REPRESSOR OF CYTOKININ DEFICIENCY1 (ROCK1) in Arabidopsis [2]. It is essential for lysosomal functions, residing at TMEM55-dependent ER-LE/lys membrane contact sites (MCSs), where it is recruited by TMEM55, a phosphatase that converts PI(4,5)P2 to PI5P on LE/lys [1]. In plants, it plays a crucial role in pollen exine formation. Genetic models, such as knockout models, are valuable for studying its functions.

In mice, Tex2 knockout leads to defects in lysosomal trafficking, digestive capacity, and lipid composition of LE/lys membranes, highlighting its importance in lysosomal functions [1]. In Arabidopsis, loss of TEX2 results in the formation of abnormal primexine, lack of primary exine elements, and failure of sporopollenin to correctly assemble into exine structures [2].

In conclusion, Tex2 is vital for lysosomal functions in mammals and pollen exine formation in plants. The gene knockout models in mice and Arabidopsis have significantly contributed to understanding its role in these biological processes, which may provide insights into related physiological and pathological conditions in different organisms.