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Domain

Ca(2+) and ATP binding cause major rearrangements of the cytoplasmic and transmembrane domains. According to the E1-E2 model, Ca(2+) binding to the cytosolic domain of the pump in the high-affinity E1 conformation is followed by the ATP-dependent phosphorylation of the active site Asp, giving rise to E1P. A conformational change of the phosphoenzyme gives rise to the low-affinity E2P state that exposes the Ca(2+) ions to the lumenal side and promotes Ca(2+) release. Dephosphorylation of the active site Asp mediates the subsequent return to the E1 conformation.

PLN and SLN both have a single transmembrane helix; both occupy a similar binding site that is situated between the ATP2A2 transmembrane helices.

Function

This magnesium-dependent enzyme catalyzes the hydrolysis of ATP coupled with the translocation of calcium from the cytosol to the sarcoplasmic reticulum lumen (PubMed:12542527, PubMed:16402920). Involved in autophagy in response to starvation. Upon interaction with VMP1 and activation, controls ER-isolation membrane contacts for autophagosome formation (PubMed:28890335). Also modulates ER contacts with lipid droplets, mitochondria and endosomes (PubMed:28890335). In coordination with FLVCR2 mediates heme-stimulated switching from mitochondrial ATP synthesis to thermogenesis (By similarity).

Isoform 2

Involved in the regulation of the contraction/relaxation cycle. Acts as a regulator of TNFSF11-mediated Ca(2+) signaling pathways via its interaction with TMEM64 which is critical for the TNFSF11-induced CREB1 activation and mitochondrial ROS generation necessary for proper osteoclast generation. Association between TMEM64 and SERCA2 in the ER leads to cytosolic Ca(2+) spiking for activation of NFATC1 and production of mitochondrial ROS, thereby triggering Ca(2+) signaling cascades that promote osteoclast differentiation and activation.

Involvement in disease

Acrokeratosis verruciformis

AKV

A localized disorder of keratinization, which is inherited as an autosomal dominant trait. Its onset is early in life with multiple flat-topped, flesh-colored papules on the hands and feet, punctate keratoses on the palms and soles, with varying degrees of nail involvement. The histopathology shows a distinctive pattern of epidermal features with hyperkeratosis, hypergranulosis and acanthosis together with papillomatosis. These changes are frequently associated with circumscribed elevations of the epidermis that are said to resemble church spires. There are no features of dyskeratosis or acantholysis, the typical findings in lesions of Darier disease.

None

The disease is caused by variants affecting the gene represented in this entry.

Darier disease

DD

A skin disorder characterized by warty papules and plaques in seborrheic areas (central trunk, flexures, scalp and forehead), palmoplantar pits and distinctive nail abnormalities. It is due to loss of adhesion between epidermal cells (acantholysis) and abnormal keratinization. Patients with mild disease may have no more than a few scattered keratotic papules or subtle nail changes, whereas those with severe disease are handicapped by widespread malodorous keratotic plaques. Some patients present with hemorrhage into acantholytic vesicles on the palms and dorsal aspects of the fingers which gives rise to black macules. In a few families affected by Darier disease, neuropsychiatric abnormalities such as mild intellectual disability, schizophrenia, bipolar disorder and epilepsy have been reported. Stress, UV exposure, heat, sweat, friction and oral contraception exacerbate disease symptoms. Clinical variants of Darier disease include hypertrophic, vesicobullous, hypopigmented, cornifying, zosteriform or linear, acute and comedonal subtypes. Comedonal Darier disease is characterized by the coexistence of acne-like comedonal lesions with typical Darier hyperkeratotic papules on light-exposed areas. At histopathologic level, comedonal Darier disease differs from classic Darier disease in the prominent follicular involvement and the presence of greatly elongated dermal villi.

None

The disease is caused by variants affecting the gene represented in this entry.

Post-translational modifications

Nitrated under oxidative stress. Nitration on the two tyrosine residues inhibits catalytic activity.

Serotonylated on Gln residues by TGM2 in response to hypoxia, leading to its inactivation.

Sequence similarities

Belongs to the cation transport ATPase (P-type) (TC 3.A.3) family. Type IIA subfamily.

Tissue specificity

Isoform 1 is widely expressed in smooth muscle and nonmuscle tissues such as in adult skin epidermis, with highest expression in liver, pancreas and lung, and intermediate expression in brain, kidney and placenta. Also expressed at lower levels in heart and skeletal muscle. Isoforms 2 and 3 are highly expressed in the heart and slow twitch skeletal muscle. Expression of isoform 3 is predominantly restricted to cardiomyocytes and in close proximity to the sarcolemma. Both isoforms are mildly expressed in lung, kidney, liver, pancreas and placenta. Expression of isoform 3 is amplified during monocytic differentiation and also observed in the fetal heart.

Cellular localization

  • Endoplasmic reticulum membrane
  • Multi-pass membrane protein
  • Sarcoplasmic reticulum membrane
  • Multi-pass membrane protein
  • Colocalizes with FLVCR2 at the mitochondrial-ER contact junction.

Alternative names

ATP2B, ATP2A2, Sarcoplasmic/endoplasmic reticulum calcium ATPase 2, SERCA2, SR Ca(2+)-ATPase 2, Calcium pump 2, Endoplasmic reticulum class 1/2 Ca(2+) ATPase

Target type

Proteins

Primary research area

Cardiovascular

Molecular weight

114757Da

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