Tts1, the fission yeast homologue of the TMEM33 family, functions in NE remodeling during mitosis.
Bottom Line: An amphipathic helix located at the C-terminus of Tts1 is important for ER shaping and modulating the mitotic NPC distribution.Of interest, the evolutionarily conserved residues at the luminal interface of the third transmembrane region function specifically in promoting SPB-NE insertion.Our data illuminate cellular requirements for remodeling the NE during "closed" nuclear division and provide insight into the structure and functions of the eukaryotic TMEM33 family.
Affiliation: Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604 firstname.lastname@example.org email@example.com.Show MeSH
Mentions: Cut11 is an essential nucleoporin that is enriched at the mitotic SPBs when they are embedded within the NE (West et al., 1998). At the restrictive temperature of 36ºC, cells carrying the temperature sensitive (ts) alleles of cut11 do not properly insert the mitotic SPBs in the NE and fail to form bipolar spindles and complete mitosis (West et al., 1998; Figure 4A). Curiously, we initially identified Tts1 as a high-copy suppressor of a tight temperature-sensitive allele of cut11, cut11-6, which carries a missense mutation causing Thr-to-Ile substitution at position 498 (Figure 4B and Supplemental Figure S3A). Of interest, among the other five previously isolated cut11 ts mutants, that is, cut11-1 to cut11-5 (West et al., 1998; Supplemental Figure S3A), increase in Tts1 levels could also suppress cut11-2/3/4/5 but not cut11-1 at 36°C (Supplemental Figure S3B). At the same time, tts1Δ displayed negative genetic interactions with all six cut11 ts alleles, including cut11-1, albeit in a milder manner as compared with the rest (Figure 4C and Supplemental Figure S3C).
Affiliation: Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604 firstname.lastname@example.org email@example.com.