Pullulan is an important polysaccharide. Although its synthetic pathway in Aureobasidium melanogenum has been elucidated, the mechanism underlying its biosynthesis as regulated by signaling pathway and transcriptional regulator is still unknown. In this study, it was found that the expression of the UGP1 gene encoding UDPG-pyrophosphorylase (Ugp1) and other genes which were involved in pullulan biosynthesis was controlled by the transcriptional activator Msn2 in the nuclei of yeast-like fungal cells. The Ugp1 was a rate-limiting enzyme for pullulan biosynthesis. In addition, the activity and subcellular localization of the Msn2 were regulated only by the cAMP-PKA signaling pathway. When the cAMP-PKA activity was low, the Msn2 was localized in the nuclei, the UGP1 gene was highly expressed, and pullulan was actively synthesized. By contrast, when the cAMP-PKA activity was high, the Msn2 was localized in the cytoplasm and the UGP1 gene expression was disabled so that pullulan was stopped, but lipid biosynthesis was actively enhanced. This study was the first to report that pullulan and lipid biosynthesis in yeast-like fungal cells were regulated by the Msn2 and cAMP-PKA signaling pathway. Elucidating the regulation mechanisms was important to understand their functions and enhance pullulan and lipid biosynthesis.

pullulan biosynthesis, Msn2, UDPG-pyrophosphorylase, yeast-like fungi, cAMP-PKA

• Compound ID: 12430
  

  -6)-a-D-Glcp-(1-4)-a-D-Glcp-(1-4)-a-D-Glcp-(1-

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  Structure type: polymer chemical repeating unit
  Trivial name: pullulan
  Compound class: EPS, O-polysaccharide, cell wall polysaccharide, glucan, polysaccharide
  Reference(s) to other database(s): GTC:G71532WE, CCSD:45938, CBank-STR:4859, GenDB:KY767023; GenDB:KY767024
  
   
  
  Aureobasidium melanogenum P16, Aureobasidium melanogenum P16 (Δmsn25 mutant), Aureobasidium melanogenum P16 (Δbcy11 mutant), Aureobasidium melanogenum P16 (Δtpk1–7 mutant), Aureobasidium melanogenum P16 (Δtpk2–8 mutant), Aureobasidium melanogenum P16 (Δtpk1/Δtpk2–16 mutant), Aureobasidium melanogenum P16 (Δtpk1/Δbcy1–3 mutant), Aureobasidium melanogenum P16 (Δtpk2/Δbcy1–7 mutant), Aureobasidium melanogenum P16 (Δac-2 mutant), Aureobasidium melanogenum P16 (Δpde1/Δpde2–9 mutant), Aureobasidium melanogenum P16 (Δtor13 mutant), Aureobasidium melanogenum P16 (Δkss6 mutant), Aureobasidium melanogenum P16 (Δste17 mutant), Aureobasidium melanogenum P16 (Δsnf8 mutant), Aureobasidium melanogenum P16 (Δhog4 mutant), Aureobasidium melanogenum BH4, Aureobasidium melanogenum TPK1H-3, Aureobasidium melanogenum TPK2H-6, Aureobasidium melanogenum ACH-7, Aureobasidium melanogenum PDEH-5, Aureobasidium melanogenum TH13, Aureobasidium melanogenum MO17, Aureobasidium melanogenum BO1, Aureobasidium melanogenum TO1–8, Aureobasidium melanogenum TO2–13, Aureobasidium melanogenum TO12-2, Aureobasidium melanogenum PDEO-8, Aureobasidium melanogenum ACO3, Aureobasidium melanogenum TO9, Aureobasidium melanogenum UO7, Aureobasidium melanogenum UP19, Aureobasidium melanogenum BA7, Aureobasidium melanogenum BP3, Aureobasidium melanogenum BU11, Aureobasidium melanogenum BUGP1–9
  CSDB ID 50677 (all data & tools)