An increase of <i>NPY1</i> expression leads to inhibitory phosphorylation of PIN-FORMED (PIN) proteins and suppression of <i>pinoid</i> (<i>pid</i>) null mutants.

ABSTRACT: The PINOID (PID) protein kinase is required for flower initiation in Arabidopsis. The pid mutants fail to initiate flowers on inflorescences, a phenotype that is mimicked by disrupting either the NAKED PINS IN YUC MUTANTS (NPY) gene family or PIN FORMED 1 (PIN1). Both PID and NPY1 have been reported to positively modulate PIN-mediated polar auxin transport. Here, we show that overexpression of NPY1 (NPY1 OE) completely suppressed pid null mutants, demonstrating that NPY1 functions downstream of PID. NPY1 OE triggered phosphorylation of PIN proteins at multiple sites that are mostly different from the previously characterized phosphorylation sites regardless of the presence of PID. Phosphorylation of the new

SUBMITTER: Mudgett M 

PROVIDER: S-EPMC12711196 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature