Total RNA was extracted from ileal myocytes using TRIzol reagent (Invitrogen).

Reverse transcription was performed using Super Script II reverse transcriptase (Invitrogen) and random hexamers.

Its biophysical properties also resemble muscarinic cation current (m I in TRPC4-deficient mouse ileal myocytes).

Two most abundant TRPC4 variants are a “full-length” TRPC4α and shorter TRPC4β (or TRPC4Δ) lacking a stretch of 84 amino acids (781-864 in the case of mouse TRPC4) in the cytosolic C terminus (Δ84AA).

The precipitated proteins were subjected to SDS-PAGE, transferred to nitrocellulose membrane, and immunoblotted using a polyclonal anti-TRPC4 antibody against an N-terminal peptide of TRPC4 (16).

—Control HEK293 cells and stable cell lines were seeded at 100,000 cells/well in wells of 96-well plates and allowed to grow for 18-24 h.

In TRPC6, this binding, in competition with calmodulin (Ca M), removes its inhibitory action and thus facilitates channel activation (7).

Here we tested the hypothesis that PIP can regulate TRPC4 channel activity.

Integration of these stimuli might enable fine-tuning of channel activation as required for coordinated functions of the endothelium or smooth muscles in the intestine and the bladder, as well as neural signaling in the nervous system.

—HEK293 cells stably expressing mouse TRPC4 (m TRPC4) isoforms were grown under culture conditions as described (16) and seeded in 35-mm dishes 2 days prior to patch clamp recordings.

The functional implications of their differential tissue expression (13, 14) are intriguing, and they call for further investigations into the differential regulation of TRPC4 isoforms.