The yeast VAPs Scs2 and Scs22 are required for NVJ integrity and micronucleophagy

• Published in: Biochemical and biophysical research communications 2024-11, Vol.734, p.150628, Article 150628
• Main Authors: Manik, Md Imran Nur, Tasnin, Most Naoshia, Takuma, Tsuneyuki, Ushimaru, Takashi
• Format: Article
• Language: English
• Subjects: Autophagy; Cell Nucleus - metabolism; Microautophagy; Micronucleophagy; NVJ; R-SNARE Proteins - genetics; R-SNARE Proteins - metabolism; rDNA; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; TORC1; Vacuoles - metabolism; VAP
• ISSN: 0006-291X; 1090-2104; 1090-2104
• DOI: 10.1016/j.bbrc.2024.150628

Microautophagy degrades cargos in the vacuole by direct engulfment of the vacuolar membrane. Micronucleophagy selectively degrades a portion of the nucleus in budding yeast. The vacuole contacts the nucleus via the nucleus–vacuole junction (NVJ), and in micronucleophagy a portion of the nucleus containing nucleolar proteins is made to protrude into the vacuole at the NVJ, followed by abscission and degradation. Microautophagy and micronucleophagy are induced by inactivation of target of rapamycin complex 1 (TORC1) protein kinase after nutrient starvation. Here, we show that the VAMP-associated proteins (VAPs) Scs2 and its paralog Scs22 are required for NVJ integrity and micronucleophagic degradation of nucleolar proteins. On the other hand, nucleolar dynamics prerequisite for micronucleophagy were not impaired in VAP mutant cells. Finally, yeast VAPs were critical for viability during prolonged nutrient starvation. This study sheds light on the emerging role of VAP in adaptation in responses to nutrient starvation. •VAPs Scs2 and Scs22 are required for integrity of the nucleus–vacuole junction.•VAPs are required for nucleophagy after TORC1 inactivation.•VAPs are essential for viability during prolonged nutrient starvation.