[Store-operated calcium entry--are all elements of the system already identified?].

Store-operated Ca2+ entry (SOCE) is an ubiquitous mechanism leading to a transient increase of Ca2+ concentration in the cytoplasm ([Ca2+]c) of a leaving cell followed by refill of the internal stores with calcium. Discovery of STIM1 and STIM2 proteins located in the endoplasmic reticulum (ER) and playing a role of sensors of calcium, led to our understanding how the calcium signal from ER is propagated to calcium release-activated calcium channels (CRAC) located in the plasma membrane, resulting in their activation, flow of calcium into a cytoplasm and activation of calcium-dependent signaling. In light of controversies existing in identification of CRAC channels (such as Oral, TRPC and others), as well as identification of mechanisms of calcium entry that are independent of the presence of calcium in the internal calcium stores, in this review we discuss the newest theories about SOCE, proteins that are engaged in this mechanism as well as pathologies related to impaired SOCE.