ATP2C1

ATP2C1 Full Name

ATPase, Ca++ transporting, type 2C, member 1

ATP2C1 Introduction

ATP2C1, frequently referred to as secretory pathway Ca²⁺/Mn²⁺-ATPase 1 (SPCA1), is a critical intracellular ion pump belonging to the P-type ATPase family. Unlike other major calcium pumps that localize to the endoplasmic reticulum or the plasma membrane, ATP2C1 is predominantly localized to the Golgi apparatus. Structurally and functionally, it operates as a magnesium-dependent enzyme that utilizes the energy derived from ATP hydrolysis to actively transport both calcium (Ca²⁺) and manganese (Mn²⁺) ions from the cytosol into the Golgi lumen.

Figure 1. A proposed model of Ca²⁺ transport by hSPCA1. (Source: Wu M, et al. 2023)

This targeted ion transport is fundamental to maintaining cellular homeostasis. By actively loading the Golgi stores with calcium and manganese, ATP2C1 establishes the highly specific luminal environment required for the proper post-translational modification, glycosylation, and sorting of newly synthesized secretory proteins. Furthermore, by acting as a cytosolic sink for these divalent cations, ATP2C1 protects cells from heavy metal toxicity and tightly regulates intracellular calcium signaling cascades. This precise regulation is particularly vital in epidermal keratinocytes. In the skin, a delicate calcium gradient dictates sequential cell differentiation and drives the structural assembly of critical cell-to-cell adhesion complexes, most notably desmosomes and tight junctions.

Clinically, the profound physiological importance of ATP2C1 is underscored by its direct causal relationship with Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus. HHD is a rare autosomal dominant genodermatosis caused by loss-of-function mutations in the ATP2C1 gene. The resulting haploinsufficiency leads to severely depleted Golgi calcium stores. In keratinocytes, this metabolic defect disrupts the intricate assembly and maintenance of intercellular junctions, culminating in suprabasal acantholysis—the abnormal physical separation of epidermal cells. Consequently, HHD patients suffer from recurrent, painful blistering, erosions, and maceration, most prominently localized in skin folds subject to friction and moisture, such as the axillae and groin. Beyond benign skin disorders, emerging research indicates that the dysregulation of ATP2C1 also impacts cancer cell biology, where its aberrant expression alters secretory pathways to support aggressive tumor microenvironments.

Alternate Names for ATP2C1

ATP2C1; ATPase, Ca++ transporting, type 2C, member 1; BCPM, benign chronic pemphigus (Hailey Hailey disease); calcium-transporting ATPase type 2C member 1; ATP2C1A; KIAA1347; PMR1; secretory pathway Ca2+/Mn2+ ATPase 1; SPCA1; HUSSY-28

• 1. Wu M, et al. Structure and transport mechanism of the human calcium pump SPCA1. Cell Res. 2023 Jul;33(7):533-545.
  2. Micaroni M, et al. ATP2C1 gene mutations in Hailey-Hailey disease and possible roles of SPCA1 isoforms in membrane trafficking. Cell Death Dis. 2016 Jun 9;7(6):e2259.