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 email@example.com firstname.lastname@example.org.Show MeSH
Mentions: We showed previously that Tts1 functions to sustain the tubular ER structure in S. pombe together with Rtn1 and Yop1 (Zhang et al., 2010). Cells lacking all three ER-shaping proteins exhibit severe division-site positioning abnormalities due to conversion of the ER into large, cortically associated sheets, preventing actomyosin ring assembly at the cellular equator (Zhang et al., 2010, 2012). Of note, lack of Tts1, Rtn1, or Yop1 individually also leads to mild division-site mispositioning, but the defects are grossly exacerbated in cells combining either of the two or all three mutations (Zhang et al., 2010). In line with this, when Tts1 was reintroduced into tts1Δ rtn1Δ yop1Δ (Δtry) background, the severe division-site positioning defects were largely corrected (Figure 2). This system afforded us a genetic tool to examine the available Tts1 mutants with respect to their presumptive ER-shaping function.
Affiliation: Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604 email@example.com firstname.lastname@example.org.