FAM 83D directs protein kinase CK 1α to the mitotic spindle for proper spindle positioning

Abstract

The concerted action of many protein kinases helps orchestrate the error‐free progression through mitosis of mammalian cells. The roles and regulation of some prominent mitotic kinases, such as cyclin‐dependent kinases, are well established. However, these and other known mitotic kinases alone cannot account for the extent of protein phosphorylation that has been reported during mammalian mitosis. Here we demonstrate that CK1α, of the casein kinase 1 family of protein kinases, localises to the spindle and is required for proper spindle positioning and timely cell division. CK1α is recruited to the spindle by FAM83D, and cells devoid of FAM83D , or those harbouring CK1α‐binding‐deficient FAM83D F283A/F283A knockin mutations, display pronounced spindle positioning defects, and a prolonged mitosis. Restoring FAM83D at the endogenous locus in FAM83D − / − cells, or artificially delivering CK1α to the spindle in FAM83D F283A/F283A cells, rescues these defects. These findings implicate CK1α as new mitotic kinase that orchestrates the kinetics and orientation of cell division.

Hyaluronan Mediated Motility Receptor (HMMR) Encodes an Evolutionarily Conserved Homeostasis, Mitosis, and Meiosis Regulator Rather than a Hyaluronan Receptor

“…That is, HMMR interacts with CHICA/FAM83D through amino acids 365-546 [18], while amino acids 574-602 act as a calcium-dependent calmodulin binding domain [19]. Through its interaction with CHICA, HMMR locates dynein light chain 1 (DYNLL1) and CK1alpha to the spindle [20], and HMMR plays a similar role in docking BACH1 at the spindle [21], although the needed interaction domain is unknown. These protein complexes, formed through interactions with the coiled-coil stalk, play critical roles in the correct orientation of the mitotic spindle and the establishment of the cell division axis.…”

“…HMMR localizes DYNLL1 at spindle poles, which dampens local dynein motor activities when brought proximal to the cell cortex [18]; 2. HMMR modulates the local activity of PLK1 and locates Ran-GTP to the spindle pole [7]; and, HMMR binds CHICA/FAM83D to locate and activate the protein kinase CK1alpha [20].…”

Pathogenic FAM83G palmoplantar keratoderma mutations inhibit the PAWS1:CK1α association and attenuate Wnt signalling.

“…Individual FAM83 proteins deliver CK1α or other CK1 isoforms to distinct subcellular compartments, and potentially to specific CK1 substrates, to influence specific cellular processes. For example, FAM83D delivers CK1α to the mitotic spindle to ensure proper spindle orientation and timely mitotic progression 28 . The PAWS1-CK1α complex appears to regulate Wnt signalling by controlling the nuclear accumulation of β-catenin downstream of the β-catenin destruction complex through as-yet-unknown mechanisms 1 .…”

IMiDs induce FAM83F degradation via an interaction with CK1α to attenuate Wnt signalling

“…Retroviruses were produced using the following constructs: pBABED.puro FAM83F WT (DU37979), pBABED.puro FAM83F F284A/F288A (DU28196), pBABED.puro FLAG CRBN (DU54685), and pBABED.puro FLAG CRBN V388I (DU64137). Retroviruses were produced by transfecting HEK-293-FT cells as previously described ( Fulcher et al, 2019 ). Briefly, 6 μg pBabe plasmid, 3.8 μg pCMV5-GAG/Pol (Clontech), and 2.2 μg pCMV5-VSV-G (Clontech) were diluted in 600 μl OptiMem (Gibco) and 24 μl PEI (1 mg/ml) was added.…”

“…All FAM83 proteins interact with CK1α, whereas FAM83A, B, E, and H also interact with CK1δ and ε ( Fulcher et al, 2018 ). Whereas the FAM83 family remains largely uncharacterised, roles for specific FAM83–CK1α complexes have been established in mitosis ( Fulcher et al, 2019 ; Fulcher & Sapkota, 2020 ) and canonical Wnt signalling ( Bozatzi et al, 2018 ; Wu et al, 2019 ; Dunbar et al, 2020 ). Given the reports of IMiD-induced degradation of CK1α, we sought to establish the effect of IMiDs on the stability of FAM83 proteins and different FAM83–CK1α complexes.…”