Studies in human and rodent systems support a role for the PAK4 gene product in signaling events associated with Parkinson disease. PAK4 encodes a member of the PAK family of serine/threonine kinases that are implicated in a wide range of biological activities. There is a single orthologous gene in Drosophila, mbt, for which multiple genetic reagents have been generated, including RNAi targeting constructs and alleles caused by insertional mutagenesis.
The human PAK4 gene has not been introduced into flies.
Animals homozygous or hemizygous for a loss-of-function mutation of mbt exhibit Parkinson-like phenotypes including age-dependent locomotor deficits, reduced lifespan, and fragmented sleep. mbt function is required in protocerebral anterior medial (PAM) cluster neurons of the brain to prevent the observed age-dependent locomotor dysfunction.
[updated Jun. 2021 by FlyBase; FBrf0222196]
Parkinson disease (PD) is a neurodegenerative disease usually typified by slow onset in mid to late adulthood; there are also early-onset and juvenile forms of the disease. Symptoms worsen over time and include resting tremor, muscular rigidity, bradykinesia [abnormal slowness of movement], and postural instability [impaired balance and coordination]; additional symptoms may include postural abnormalities, dysautonomia [symptoms caused by malfunction of the autonomic nervous system], dystonic cramps, and dementia. Parkinson disease is the second-most common neurodegenerative disease (after Alzheimer disease), affecting approximately 1% of the population over 50 (Polymeropoulos et al., 1996, pubmed:8895469). [from MIM:168600; 2013.07.23]
Parkinson disease is described as early-onset disease if signs and symptoms begin before age 50. Early-onset cases that begin before age 20 may be referred to as juvenile-onset disease. [from Genetics Home Reference, GHR_condition:parkinson-disease, 2015.02.13]
Studies in human and rodent systems implicate PAK4 as an important mediator in PD-associated signaling processes (FBrf0249216 and references cited therein).
PAK4 encodes a serine/threonine protein kinase that plays a role in a variety of different signaling pathways including cytoskeleton regulation, cell migration, growth, proliferation, or cell survival. PAK proteins are critical effectors that link Rho GTPases to cytoskeleton reorganization and nuclear signaling. [Gene Cards, PAK4; 2012.06.22]
Many to one: 3 human genes to 1 Drosophila gene; multiple additional related genes in both species.
High-scoring ortholog of human PAK4 and PAK5; low- to moderate-scoring ortholog of PAK6 (1 Drosophila to 3 human; multiple additional related genes in both species). Dmel\mbt shares 50% identity and 60% similarity with the human PAK4 gene.