High impact information on PSKH1

• We have dissected the molecular determinants involved in targeting the protein serine kinase PSKH1 to the endoplasmic reticulum (ER), the Golgi apparatus, and the plasma membrane (PM) [1].
• Mutants of the protein serine kinase PSKH1 disassemble the Golgi apparatus [1].
• Biochemical studies demonstrated that PSKH1 is myristoylated on glycine 2 and palmitoylated on cysteine 3 [1].
• The amino-terminal of PSKH1 revealed a striking similarity to the often acylated Src homology domain 4 (SH4)-harboring nonreceptor tyrosine kinases [1].
• Immunoelectron microscopy revealed that the dually acylated amino-terminal domain (in fusion with EGFP) was targeted to Golgi membranes as well as to the plasma membrane (PM), suggesting that the amino-terminal domain provides PSKH1 with membrane specificity dependent on its fatty acylation status [1].

Biological context of PSKH1

• PSKH1 displays the highest level of similarity with rat CaM kinase I (50. 2%) over 259 amino acids in the conserved catalytic region, but lacks significant homology with proteins in the database outside the catalytic core [2].

Anatomical context of PSKH1

• Our results suggest a structural and regulatory role of PSKH1 in maintenance of the Golgi apparatus, a key organelle within the secretory pathway [1].
• 6. PSKH1 is expressed in all tissues and cell lines tested as shown by Northern blots, with the highest level of abundance in testis [2].
• Polyclonal antibodies have been raised, and indirect immunofluorescence microscopy of untransfected COS-1 cells suggests that PSKH1 is localized in the Brefeldin A-sensitive Golgi compartment, at centrosomes, in the nucleus with a somewhat speckle-like presence, and more diffusely in the cytoplasm [2].
• Although no direct interaction was observed between PSKH1 and any of the SR proteins tested in pull-down or yeast two-hybrid assays, forced expression of PSKH1-FLAG was shown to stimulate distal splicing of an E1A minigene in HeLa cells [3].

References