High impact information on CHS5

• Arf1p, Chs5p and the ChAPs are required for export of specialized cargo from the Golgi [1].
• The temporal and spatial regulation of chitin synthesis was investigated during vegetative growth and mating of Saccharomyces cerevisiae by localization of the putative catalytic subunit of chitin synthase III, Chs3p, and its regulator, Chs5p [2].
• Targeting of chitin synthase 3 to polarized growth sites in yeast requires Chs5p and Myo2p [2].
• Epitope-tagged Chs5p also localizes to cytoplasmic patches; these patches contain Kex2p, a late Golgi-associated enzyme [2].
• However, only the class IV CHS genes chs7 and chs5 are crucial for shaping yeast cells and hyphae ex planta [3].

Biological context of CHS5

• DNA sequence analysis reveals that CHS5 encodes a unique polypeptide of 671 amino acids with a molecular mass of 73,642 Da [4].
• The effects of deletion of CHS5 indicate that it is not essential for yeast cell growth; however, it is important for mating [4].
• Transformation of the mutant with a plasmid carrying CHS5 restored Calcofluor sensitivity, wild-type cell wall chitin levels, and chitin synthase III activity levels [4].
• To further understand the role of CHS5 in yeast, the CHS5 gene was cloned by complementation of the Calcofluor resistance phenotype of a chs5 mutant [4].
• We have identified and characterized two homologous yeast proteins, Sbe2p and Sbe22p, through their suppression of a chs5 spa2 mutant strain defective in chitin synthesis and cell morphogenesis [5].

Anatomical context of CHS5

• Thus, we suggest a model in which Sbe2p and Sbe22p are involved in the transport of cell wall components from the Golgi apparatus to the cell surface periphery in a pathway independent of Chs5p [5].
• Chs5/6 Complex: A Multiprotein Complex That Interacts with and Conveys Chitin Synthase III from the Trans-Golgi Network to the Cell Surface [6].
• The traffic of Chs3p to the cell surface from the trans-Golgi network (TGN) depends on two proteins, Chs5p and Chs6p, which sort selected cargo proteins into secretory vesicles [6].

Physical interactions of CHS5

• Chs5p is a late-Golgi protein required for the polarized transport of the chitin synthase Chs3p to the membrane [7].

Other interactions of CHS5

• However, chs5 cells produce more chitin than chs3 mutants, indicating that CHS5 plays a role in other processes besides chitin synthesis [4].
• In addition, mating efficiency is much lower in fus1 fus2 x chs5 than in fus1 fus2 x wild type crosses [4].
• Moreover, cells overexpressing Ypt32p accumulate chitin at the cell surface independent of Chs5p [8].

References