STIM1 is an essential and conserved component of store-operated Ca²+ channel function. This study identifies STIM1 as a critical regulator of store-operated Ca²+ (SOC) influx and CRAC channel activity in Drosophila S2 cells and mammalian cells. Using RNA interference (RNAi), the researchers demonstrated that STIM1 is required for SOC influx and CRAC channel function. Knockdown of STIM1 in Drosophila S2 cells significantly reduced TG-dependent Ca²+ entry, while overexpression of STIM1 in HEK293 cells modestly enhanced TG-induced Ca²+ entry. STIM1 is a type I transmembrane protein with two mammalian homologues, STIM1 and STIM2. The study shows that STIM1, but not STIM2, regulates SOC influx in human cells. STIM1 is conserved from Drosophila to mammalian cells and plays an essential role in SOC influx and CRAC channel activity. The study also shows that STIM1 is required for normal activity of CRAC channels in S2 cells. In mammalian cells, STIM1 suppression significantly reduced TG-dependent Ca²+ influx in Jurkat T cells. STIM1 suppression also reduced CRAC current density in Jurkat T cells. STIM1 modulates SOC influx in mammalian cells. The study confirms that STIM1 is required for SOC influx and CRAC channel activity in Drosophila and human cells. STIM1 is a key component in regulating SOC influx and CRAC channel function. The study provides evidence that STIM1 is a conserved component of SOC and CRAC channels. The results suggest that STIM1 is a key regulator of SOC influx and CRAC channel function. The study highlights the importance of STIM1 in regulating SOC influx and CRAC channel function. The findings indicate that STIM1 is a critical component of SOC and CRAC channels. The study demonstrates that STIM1 is essential for SOC influx and CRAC channel function. The results suggest that STIM1 is a conserved component of SOC and CRAC channels. The study provides evidence that STIM1 is a key regulator of SOC influx and CRAC channel function. The findings indicate that STIM1 is a critical component of SOC and CRAC channels. The study highlights the importance of STIM1 in regulating SOC influx and CRAC channel function. The results suggest that STIM1 is a conserved component of SOC and CRAC channels. The study demonstrates that STIM1 is essential for SOC influx and CRAC channel function. The findings indicate that STIM1 is a key regulator of SOC influx and CRAC channel function. The study provides evidence that STIM1 is a conserved component of SOC and CRAC channels. The results suggest that STIM1 is a critical component of SOC and CRAC channels. The study highlights the importanceSTIM1 is an essential and conserved component of store-operated Ca²+ channel function. This study identifies STIM1 as a critical regulator of store-operated Ca²+ (SOC) influx and CRAC channel activity in Drosophila S2 cells and mammalian cells. Using RNA interference (RNAi), the researchers demonstrated that STIM1 is required for SOC influx and CRAC channel function. Knockdown of STIM1 in Drosophila S2 cells significantly reduced TG-dependent Ca²+ entry, while overexpression of STIM1 in HEK293 cells modestly enhanced TG-induced Ca²+ entry. STIM1 is a type I transmembrane protein with two mammalian homologues, STIM1 and STIM2. The study shows that STIM1, but not STIM2, regulates SOC influx in human cells. STIM1 is conserved from Drosophila to mammalian cells and plays an essential role in SOC influx and CRAC channel activity. The study also shows that STIM1 is required for normal activity of CRAC channels in S2 cells. In mammalian cells, STIM1 suppression significantly reduced TG-dependent Ca²+ influx in Jurkat T cells. STIM1 suppression also reduced CRAC current density in Jurkat T cells. STIM1 modulates SOC influx in mammalian cells. The study confirms that STIM1 is required for SOC influx and CRAC channel activity in Drosophila and human cells. STIM1 is a key component in regulating SOC influx and CRAC channel function. The study provides evidence that STIM1 is a conserved component of SOC and CRAC channels. The results suggest that STIM1 is a key regulator of SOC influx and CRAC channel function. The study highlights the importance of STIM1 in regulating SOC influx and CRAC channel function. The findings indicate that STIM1 is a critical component of SOC and CRAC channels. The study demonstrates that STIM1 is essential for SOC influx and CRAC channel function. The results suggest that STIM1 is a conserved component of SOC and CRAC channels. The study provides evidence that STIM1 is a key regulator of SOC influx and CRAC channel function. The findings indicate that STIM1 is a critical component of SOC and CRAC channels. The study highlights the importance of STIM1 in regulating SOC influx and CRAC channel function. The results suggest that STIM1 is a conserved component of SOC and CRAC channels. The study demonstrates that STIM1 is essential for SOC influx and CRAC channel function. The findings indicate that STIM1 is a key regulator of SOC influx and CRAC channel function. The study provides evidence that STIM1 is a conserved component of SOC and CRAC channels. The results suggest that STIM1 is a critical component of SOC and CRAC channels. The study highlights the importance