Ca_V1.2 dynamics in native male arterial myocytes

L-type Ca_V1.2 channels are key regulators of cellular function in diverse cell types, controlling processes that range from gene expression to muscle contraction. In arterial myocytes, Ca_V1.2 channels traffic to the plasma membrane and assemble into clusters that control Ca²⁺ influx. Changes in the size and number of these Ca_V1.2 clusters have been linked to altered channel and vascular function in diabetic hyperglycaemia, angiotensin II (Ang II) signalling and hypertension. Yet, the dynamics governing the distribution of vascular Ca_V1.2 at the plasma membrane remain poorly understood. Here, we found that microtubule-mediated transport actively shapes Ca_V1.2 distribution under hyperglycaemia and Ang II signalling. Employing high-resolution imaging, we tracked live Ca_V1.2 trafficking in male arterial myocytes using a dual approach: unpassaged cells expressing vascular Ca_V1.2- and freshly isolated cells from a Ca_V1.2-mClover2 knock-in mouse, which enabled endogenous channel visualization in native tissue. By recreating diabetic hyperglycaemia (20 mM d-glucose) and enhancing Ang II signalling in vitro, we uncovered distinct Ca_V1.2 trafficking patterns in both cultured and freshly isolated arterial myocytes that were dependent on an intact microtubular network. Importantly, microtubule disruption abolished Ca_V1.2 dynamics and prevented Ang II-induced calcium elevations in both isolated myocytes and intact arteries. These findings identify microtubule-dependent Ca_V1.2 trafficking as a key mechanism by which hyperglycaemia and Ang II signalling may drive channel reorganization and calcium dysregulation. The results have implications for vascular dysfunction in diabetes and hypertension, and open new potential therapeutic avenues targeting the cellular transport machinery. Moreover, the Ca_V1.2-mClover2 mouse provides a useful tool for investigating native channel behaviour in living tissues across physiological and pathological contexts. KEY POINTS: Live-cell total internal reflection fluorescence and spinning-disk confocal imaging revealed that vascular Ca_V1.2 channels exhibit distinct perimembrane behaviours in male arterial myocytes, including kiss-and-stay, kiss-and-run, and homotypic fusion and fission events. Microtubules are essential for vascular Ca_V1.2 structural dynamics, with nocodazole-induced microtubule disruption significantly reducing channel mobility, speed and displacement. Hyperglycaemic or angiotensin II-stimulated environments rapidly increased vascular Ca_V1.2 clustering at the plasma membrane, and microtubule disruption abolished these pathological elevations in clustering and intracellular Ca²⁺ in both isolated myocytes and intact arteries. A CRISPR/Cas9-generated Ca_V1.2-mClover2 knock-in mouse enabled endogenous channel visualization in native tissue, providing a transformative tool for investigating Ca_V1.2 behaviour in physiological and pathological contexts.