SYVN1 and Glucose intolerance: However, a state of HRD1 KD exists in all cells upon diminished expression of SEL1L — its interaction confers HRD1 stability in mammalian cells (11, 14, 15) and in yeast (16) — but rather than improving glucose-stimulated insulin secretion (GSIS) and blood glucose homeostasis, deficient ERAD capacity was found to result in diminished GSIS with development of whole animal glucose intolerance (6).