PSKH

PSKH1 (protein serine kinase H1) is a serine/threonine kinase belonging to the CAMK kinase family and displays localization to the Golgi apparatus, centrosomes, endoplasmic reticulum-associated membranes, cytoplasm, and nuclear speckles, indicating roles across multiple intracellular compartments^[5][1]. Mechanistically, PSKH1 has been characterized as a splice factor compartment-associated kinase that may regulate pre-mRNA processing through phosphorylation of serine/arginine-rich (SR) splicing factors, thereby influencing their intranuclear trafficking and local availability for alternative splicing events^[1][2]. Consistent with this function, PSKH1 concentrates within nuclear splicing factor compartments while also maintaining membrane-associated pools through lipid modifications that contribute to subcellular targeting^[1][2]. Experimental studies further demonstrated that altered PSKH1 activity affects Golgi organization, linking kinase-dependent signaling to intracellular membrane dynamics and protein trafficking pathways^[6]. In disease-related contexts, recent genetic and functional evidence identified PSKH1 as a critical factor in kidney development, and pathogenic variants have been associated with a hepatorenal ciliopathy presenting as progressive familial intrahepatic cholestasis type 13^[7][3]. Compared with the related paralog PSKH2, which is classified as a pseudokinase lacking canonical catalytic activity, PSKH1 retains active kinase function and therefore represents the enzymatically competent member of this kinase subfamily^[7]. For experimental applications, PSKH1 activity can be modulated by calcium-sensor proteins and calmodulin-dependent mechanisms, providing a framework for investigating kinase regulation within secretory and RNA-processing pathways^[4].