HER1

HAX1
Identifiers
Symbol	?
NCBI gene	10456
HGNC	4859
OMIM	604298
RefSeq	NM_006118
UniProt	O00165
Search for Structures Swiss-model Domains InterPro

HAX1 (HCLS1 associated protein X-1) is a protein encoded by the HAX1 gene in humans. It is involved in various cellular processes, including apoptosis, cell migration, and calcium homeostasis. HAX1 is ubiquitously expressed in human tissues and plays a critical role in maintaining the integrity of the mitochondrial membrane.

Structure

HAX1 is a small protein consisting of 279 amino acids. It contains several domains that facilitate its interaction with other proteins and cellular structures. The protein is predominantly localized in the mitochondria but can also be found in the cytoplasm and the endoplasmic reticulum.

Function

HAX1 is primarily known for its role in apoptosis regulation. It interacts with several proteins involved in the apoptotic pathway, including Bcl-2 family members, to inhibit apoptosis and promote cell survival. Additionally, HAX1 is involved in the regulation of calcium ion concentration within cells, which is crucial for various cellular functions.

HAX1 also plays a role in cell migration by interacting with cytoskeletal elements. This function is particularly important in immune cells, where HAX1 facilitates the movement and function of these cells in response to external stimuli.

Clinical Significance

Mutations in the HAX1 gene are associated with severe congenital neutropenia (SCN), a condition characterized by a deficiency of neutrophils, leading to increased susceptibility to infections. Patients with SCN often present with recurrent bacterial infections and may require treatment with granulocyte colony-stimulating factor (G-CSF) to increase neutrophil counts.

Interactions

HAX1 interacts with several proteins, including:

• HS1 (Hematopoietic lineage cell-specific protein 1)
• Bcl-2 family proteins
• Caspase-9
• Calcium-binding proteins

These interactions are crucial for its role in apoptosis inhibition and calcium homeostasis.

Research Directions

Current research on HAX1 focuses on understanding its precise mechanisms in apoptosis and cell migration, as well as its potential role in other diseases beyond SCN. There is also interest in exploring HAX1 as a therapeutic target for conditions involving dysregulated apoptosis.

Also see

• Apoptosis
• Mitochondria
• Neutropenia
• Calcium signaling