Here, we show that increasing intracellular tau could upregulate mRNA and protein levels of TRPC1 (transient receptor potential channel 1) with an activated store‐operated calcium entry (SOCE), an increased intraneuronal steady‐state [Ca2+]i, an enhanced endoplasmic reticulum (ER) stress, an imbalanced protein kinases and phosphatase, and an aggravated tauopathy. Here, MAPT is linked to tauopathy.