A new phosphate-starvation response in fission yeast requires the endocytic function of myosin I.

Endocytosis is essential for uptake of many substances into the cell, but how it links to nutritional signalling is poorly understood. Here, we show a new role for endocytosis in regulating the response to low phosphate in Schizosaccharomyces pombe. Loss of function of myosin I (Myo1), Sla2/End4 or Arp2, proteins involved in the early steps of endocytosis, led to increased proliferation in low-phosphate medium compared to controls. We show that once cells are deprived of phosphate they undergo a quiescence response that is dependent on the endocytic function of Myo1. Transcriptomic analysis revealed a wide perturbation of gene expression with induction of stress-regulated genes upon phosphate starvation in wild-type but not Δmyo1 cells. Thus, endocytosis plays a pivotal role in mediating the cellular response to nutrients, bridging the external environment and internal molecular functions of the cell.

Predictive factors for pregnancy after controlled ovarian stimulation and intrauterine insemination: A retrospective analysis of 4146 cycles.

BACKGROUND: The variability in indications and low rate of pregnancy compared to IVF have led many authors to dismiss IUI and offer IVF first-line instead. OBJECTIVES: To determine what are the predictive factors for clinical pregnancy (CP) and live birth (LB) in intrauterine insemination (IUI) cycles following controlled ovarian stimulation (COS). METHODS: Retrospective unicentric study, between January 2009 and December 2016. Patients aged 18 to <43 years who had an IUI following COS with gonadotropins. Statistical analysis was performed using Chi square and logistic regression. RESULTS: 4146 cycles (1312 couples) included. Mean age was 34.7 +/- 4years. LBR per couple was 39% for anovulatory infertility compared to (p < 0.05) unex-plained infertility (28.6%), mixed (23.4%), male factor (20.1%), unilateral tubal (14.2%), low ovarian reserve (13.2%), and endometriosis (stage I and II) (11.1%). Multivariate analysis showed the following factors were associated with CP: Cycle rank ≤3 (Odds ratio (OR) = 1.5, 95% CI: 1.2-1.9, p < 0.001), age <38 years (OR = 1.5, 95% CI: 1.2-2, p < 0.001), ≥2 preovulatory follicles (OR = 1.4, 95% CI: 1.1-1.8, p = 0.004), TMSC ≥ 5 millions (OR = 1.8, 95% CI: 1.3-2.4, p < 0.001). Endometriosis, low ovarian reserve, unilateral tubal and male factor had a negative impact on CPR (OR = 0.3, 95% CI: 0.1-0.5, p < 0.001; OR = 0.4, 95% CI: 0.3-0.7, p < 0.001; OR = 0.5 95% CI: 0.3-0.9, p = 0.01; OR = 0.6, 95% CI: 0.4-0.8, p = 0.002 respectively) compared to anovulatory infertility. CONCLUSION: We confirm that IUI can be an efficient treatment in selected indications. Young patients with anovulatory infertility seem to be the ideal candidates, with a 39% LBR per couple.