Involved in pre-mRNA splicing by mediating structural transitions of the spliceosome during the catalytic step. Facilitates expression of genes involved in auxin-mediated development including male-gametophyte transmission, apical-basal patterning of embryonic and gynoecium development, stamen development, phyllotactic flower positioning, and vascular development (PubMed:25384462). Also involved in root-meristem maintenance and planar polarity of root-hair positioning (PubMed:26237376). Acts as a component of RNA silencing that regulates distinct classes of endogenous small RNAs. Functions as a positive regulator of plant immunity (PubMed:25902521). ATP + H2O = ADP + H(+) + phosphate Interacts with the Phytophthora PSR1 protein. Binds to the spliceosome. Preferentially expressed in developing organs. Narrow rosette leaves with altered venation pattern. Silencing of PINP1 renders defects in small RNA accumulation, developmental defects and hypersensitivity to Phytophthora infection. Belongs to the DEAD box helicase family. DEAH subfamily. PRP16 sub-subfamily.