Differential turnover of Nup188 controls its levels at centrosomes and role in centriole duplication

Abstract

NUP188 encodes a scaffold component of the nuclear pore complex (NPC) and has been implicated as a congenital heart disease gene through an ill-defined function at centrioles. Here, we explore the mechanisms that physically and functionally segregate Nup188 between the pericentriolar material (PCM) and NPCs. Pulse-chase fluorescent labeling indicates that Nup188 populates centrosomes with newly synthesized protein that does not exchange with NPCs even after mitotic NPC breakdown. In addition, the steady-state levels of Nup188 are controlled by the sensitivity of the PCM pool, but not the NPC pool, to proteasomal degradation. Proximity-labeling and super-resolution microscopy show that Nup188 is vicinal to the inner core of the interphase centrosome. Consistent with this, we demonstrate direct binding between Nup188 and Cep152. We further show that Nup188 functions in centriole duplication at or upstream of Sas6 loading. Together, our data establish Nup188 as a component of PCM needed to duplicate the centriole with implications for congenital heart disease mechanisms.

Mitotic Kinases Aurora-A, Plk1, and Cdk1 Interact with Elk-1 Transcription Factor through the N-Terminal Domain

“…Other mitotic phase-dependent partners of Elk-1 that are not referenced in either Plk or Aur/Plk phosphoproteomes include G1&M partners nucleoporin NUP188 and MAPK3 (ERK1), M phase partners histone acetyltransferase CREBBP and MAPK8 (JNK), and noncell cycle partners RNA binding protein EWSR1, cadherin CDH3, tubulin TUBB8, hypoxia-inducible protein HIGD1A, amyloid precursor protein APP, ubiquitin-conjugating enzyme UBE21, and mitochondrial proteins SLC25A1 (mitochondrial citrate transporter), SLC25A11 (mitochondrial malate carrier), and SLC25A10 (mitochondrial dicarboxylate carrier). Nucleoporin NUP188 has been shown to localize to spindle poles during mitosis and regulate centriole duplication as well as chromosome segregation [ 42 , 43 ]. EWS RNA binding protein 1, or EWSR1, is a multifunctional protein; it was found to be spindle-associated and to regulate microtubule acetylation in mitotic spindles in a cell cycle-dependent manner [ 44 ].…”

From the sideline: Tissue‐specific nucleoporin function in health and disease, an update

“…Mechanistic details remain to be elucidated, but Del Viso et al suggested that NUP188 has a more ample function at the cilia bases than at NPCs [69]. Consistently, it appears that newly synthesised NUP188 is recruited to centrosomes at all stages of the cell cycle and that no exchange with the pool of NUP188 at NPCs occurs [70]. At centrosomes, NUP188 is found in close proximity to the inner centrosomal protein CEP152 and both proteins co-immunoprecipitate when over-expressed in human cells, suggesting that NUP188 is indeed a bona fide constituent of the centrosome.…”

“…At centrosomes, NUP188 is found in close proximity to the inner centrosomal protein CEP152 and both proteins co‐immunoprecipitate when over‐expressed in human cells, suggesting that NUP188 is indeed a bona fide constituent of the centrosome. Along this line, siRNA‐mediated knock‐down of NUP188 in human cells compromised centrosome organisation and duplication [70].…”

Non-classical functions of nuclear pore proteins in ciliopathy

“…As mentioned earlier, contrary to the CPC hypothesis, super-resolution imaging exposed Nup188’s barrel-like structures at the cilium base, contrasting with NPC-like ring formation ( Del Viso et al, 2016 ). Studies have positioned NUP188 below the transition zone as a constituent of pericentriolar material (PCM), directly interacting with CEP152, a PCM component ( Del Viso et al, 2016 ; Vishnoi et al, 2020 ).…”

“…Although NUP93 binds to either NUP205 or NUP188, they cannot be simultaneously bound, as shown in vitro reconstitution studies ( Amlacher et al, 2011 ; Beck and Hurt, 2017 ). Nup188’s role in mitotic chromosome alignment has been documented ( Itoh et al, 2013 ; Vishnoi et al, 2020 ). Importantly, patients harbouring recessive NUP205 and NUP188 mutations exhibited diverse clinical phenotypes.…”