Functional interactome of Aquaporin 2 subfamily reveals new physiological functions in Arabidopsis thaliana

Aquaporiuns plasma membrane proteins are intercellular channel proteins found in different cellular compartments, facilitate the water flow and control the movement of gases and solutes across the cellular plasma membranes. This in silico analysis is focused on the subfamily plasma membrane intrinsic protein 2 (AtPIP2), predicting their interactome homolog’s and 3-D models. AtPIP2 homologs interact with many proteins with different plant physiological roles in Arabidopsis thaliana including PIP1 subfamily, involved in the transport of water, controlling the  cell turgor and cell expansion and involved in root water uptake respectively. The results revealed that AtPIP2-5, AtPIP2-7 and AtPIP2-8 interact with Syntaxin 132 protein (SYP132), functioning in vesicle trafficking in the secretory pathway. In Medicago tarancula  SYP132 protein  is shown to function in infection thread development or growth and the early stages of symbiosome formation.  Another important interaction of PIP2-5 and PIP2-7 proteins is with NAC transcription factor-like 9 proteins (NTL9), which is shown to control the floral development. In addition,  AtPIP2-2 and AtPIP2-3 proteins  are shown to  interact with Nodulin-26-like major intrinsic protein subfamily (NIPs) ,where AtNIP2;1 displays transport of lactic acid and therefore  may play a role in adaptation to lactic fermentation under anaerobic conditions. This in silico analysis revealed that AtPIP2 subfamily may have additional roles in other physiological functions such as symbiosome formation, abiotic stress control and possibly in lactic acid transport