AATK - Serine/threonine-protein kinase LMTK1 |Elisa - Clia - Antibody - Protein

Background

AATK (Apoptosis-Associated Tyrosine Kinase), also known as LMTK1 (Lemur Tyrosine Kinase 1), is a member of the serine/threonine-protein kinase family. PTKs (Protein Tyrosine Kinases) facilitate the transfer of the gamma-phosphoryl group from ATP to tyrosine (Tyr) residues. LMTK1, also known as Apoptosis-associated tyrosine kinase (AATK) or AATYK, is a cytoplasmic kinase with an extensive C-terminal region. The expression of LMTK1 is elevated during growth arrest and apoptosis in myeloid cells . LMTK1 is implicated in neural differentiation and serves as a regulator for the Na-K-2Cl cotransporter, a membrane protein involved in cell proliferation, survival, epithelial transport, and blood pressure control. The protein comprises a tyrosine kinase domain at the N-terminal end and a proline-rich domain at the C-terminal end. Studies on the mouse homologue suggest its potential role in inducing growth arrest and apoptosis in myeloid precursor cells. Additionally, it may play a part in promoting differentiation in neuronal cells . Recent reports also highlight its suppressive effect on melanoma development

Structural Features

AATK/LMTK1 is characterized by several structural features that facilitate its function:

• Kinase Domain: Responsible for its enzymatic activity, allowing it to phosphorylate target proteins on serine/threonine residues.
• Transmembrane Domains: Multiple transmembrane domains anchor the protein in cellular membranes, particularly in the endoplasmic reticulum and Golgi apparatus.
• Regulatory Domains: Additional regions that may modulate kinase activity and facilitate interactions with other cellular proteins.

Subtypes and Classification

AATK/LMTK1 does not have widely recognized subtypes, but it can be classified based on its structural and functional characteristics:

• Serine/Threonine Kinase: Due to its enzymatic activity in phosphorylating serine and threonine residues.
• Transmembrane Kinase: Reflecting its localization in membrane-bound organelles and involvement in intracellular signaling.

Ligands and Interactions

AATK/LMTK1 interacts with a variety of substrates and regulatory proteins, including:

• Cyclin-Dependent Kinases (CDKs): Interaction with CDKs influences cell cycle regulation and neuronal differentiation.
• 14-3-3 Proteins: These regulatory proteins bind to phosphorylated sites on AATK/LMTK1, affecting its localization and activity.
• Microtubules: AATK/LMTK1 associates with microtubules, playing a role in cytoskeletal organization and intracellular transport.

Physiological Functions

AATK/LMTK1 is involved in multiple cellular processes:

• Neuronal Differentiation: Plays a critical role in the differentiation and development of neurons, affecting neurogenesis and axon outgrowth.
• Apoptosis: Regulates apoptotic pathways, contributing to programmed cell death under certain conditions.
• Intracellular Signaling: Participates in signaling pathways that regulate various cellular functions, including cell cycle progression and survival.

Clinical Implications

Alterations in AATK/LMTK1 expression or function are associated with several clinical conditions:

• Neurological Disorders: Dysregulation of AATK/LMTK1 has been implicated in neurodegenerative diseases and conditions affecting neural development.
• Cancer: Overexpression or mutation of AATK/LMTK1 can contribute to oncogenic processes, promoting tumor cell survival and proliferation.
• Psychiatric Disorders: Variations in the function of AATK/LMTK1 may influence the risk of psychiatric conditions, although this is an area of ongoing research.