Expression of a truncated form of inositol 1,4,5-trisphosphate receptor type III in the cytosol of DT40 triple inositol 1,4,5-trisphosphate receptor-knockout cells

Vimentin and the K-Ras-induced actin-binding protein control inositol-(1,4,5)-trisphosphate receptor redistribution during MDCK cell differentiation.

“…The latter are pre-B-lymphocytes in which all three InsP 3 R genes have been disrupted (Sugawara et al, 1997). As previously described (Guillemette et al, 2005) and illustrated in Fig. 2D, they are entirely devoid of InsP 3 R1 but still contain, in the cytosol, a truncated form of InsP 3 R3.…”

The diacylgylcerol-sensitive TRPC3/6/7 subfamily of cation channels: functional characterization and physiological relevance

“…In agreement with this notion, application of the calmodulin inhibitor calmidazolium resulted in enhanced TRPC3 channel activity [85]. These mechanisms of activation and deactivation have been challenged, because in a DT40 cell line devoid of all three forms of IP 3 receptors, TRPC3 is activated by agonists to the same extent as in wild-type cells [74], yet it was recently discovered that these cells still express fragments of IP 3 receptors that could bind to TRPC6 [19] and probably other TRPC channels. However, in the same TRPC3-expressing HEK293 cell line previously used to develop the conformational coupling hypothesis, TRPC3 activation was demonstrated to function independently of the IP 3 receptor [65].…”

Role of Inositol Trisphosphate Receptors in Autophagy in DT40 Cells

“…Recently, Vicencio et al (37) reported no difference in autophagy between wild-type and TKO DT40 cells. Because knockdown or inhibition of IP 3 Rs has previously been shown to enhance autophagy (17), the lack of a difference in autophagy between the two cell lines is surprising and was attributed to an adaptive alteration of the TKO DT40 cells or to the continued presence of the ligand binding domain of the type III IP 3 R in the TKO cells (50). The latter explanation seems unlikely because a functionally inactive IP 3 R fragment would not be expected to support autophagy based on the experiments with the defective pore mutant.…”