Signal-regulated Unmasking of Nuclear Localization Motif in the PAS Domain Regulates the Nuclear Translocation of PASK

Michael Xiao, Sajina Dhungel, Roksana Azad, Denize C. Favaro, Rajaian Pushpabai Rajesh, Kevin H. Gardner, Chintan K. Kikani

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The ligand-regulated PAS domains are one of the most diverse signal-integrating domains found in proteins from prokaryotes to humans. By biochemically connecting cellular processes with their environment, PAS domains facilitate an appropriate cellular response. PAS domain-containing Kinase (PASK) is an evolutionarily conserved protein kinase that plays important signaling roles in mammalian stem cells to establish stem cell fate. We have shown that the nuclear translocation of PASK is stimulated by differentiation signaling cues in muscle stem cells. However, the mechanistic basis of the regulation of PASK nucleo-cytoplasmic translocation remains unknown. Here, we show that the PAS-A domain of PASK contains a putative monopartite nuclear localization sequence (NLS) motif. This NLS is inhibited in cells through intramolecular association with a short linear motif, termed the PAS Interacting Motif (PIM), found upstream of the kinase domain. This interaction serves to retain PASK in the cytosol in the absence of signaling cues. Consistent with that, we show that metabolic inputs induce PASK nuclear import, likely by disrupting this association. We suggest that a route for such linkage may occur through the PAS-A ligand binding cavity. We show that PIM recruitment and artificial ligand binding to the PAS-A domain occur at neighboring locations that could facilitate metabolic control of the PAS-PIM interaction. Thus, the intramolecular interaction in PASK integrates metabolic signaling cues for nuclear translocation and could be targeted to control the balance between self-renewal and differentiation in stem cells.

Original languageEnglish
Article number168433
JournalJournal of Molecular Biology
Volume436
Issue number3
DOIs
StatePublished - Feb 1 2024

Bibliographical note

Publisher Copyright:
© 2023 Elsevier Ltd

Funding

This work was supported by grants from the National Institutes of Health ( R01 AR073906 to CKK, R01 GM106239 to KHG, F31 GM142258 to RA).

FundersFunder number
National Institutes of Health (NIH)R01 GM106239, R01 AR073906, F31 GM142258

    Keywords

    • Glutamine signaling
    • NMR
    • PASK
    • Protein-peptide interaction
    • Solution structure

    ASJC Scopus subject areas

    • Biophysics
    • Structural Biology
    • Molecular Biology

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