vha3: Vacuolartype Proton Translocating ATPase

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vha-3 Vacuolar-type Proton Translocating ATPase

• Sameera Kongara

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Clones
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BLAST Results
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BLAST Results
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Vha-3

• 161 amino acids codes for Subunit c of Vo domain
• Protein 100 identical to Vha-2
• Expressed in gastrointestinal,
• hypodermal and excretory cells
• Required for oogenesis, Expression of
  vha-3
• not for embryogenesis

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V-type ATPases

• Present in vacuoles, endosomes and Golgi
• Contains 2 major domains Vo (membrane bound) and
  V1 (catalytic)
• Vo Glu residue on Subunit c required
• Regulated by dissociation of Vo and V1

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Some Important Functions of V-ATPases

• Bone remodeling
• Receptor- Mediated Endocytosis Cholesterol
  metabolism
• Immune System Macrophages

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V-type ATPases in Osteoclasts

• Osteoclasts use ATPases to remodel bones
• Antibiotic Bafilomycin appears to bind to Subunit
  c to inhibit V- ATPase

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Cholesterol metabolism

• Acidic environment necessary for dissociation of
  receptors from ligand

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V-ATPases in Cancer

• Cellular acidification triggers apoptosis
• Extracellular environment more acidic in tumor
  cells
• EXPRESSION OF V-ATPase IN TUMORS
• V-ATPases overexpressed in plasma membranes of
  highly metastatic tumors
• pH difference can be used for effective drug
  delivery