May play a role in the pathogenesis of an uncommon form of kidney cancer through its association with an inherited disorder of the hair follicle (fibrofolliculomas). May be a tumor suppressor. May be involved in colorectal tumorigenesis. May be involved in energy and/or nutrient sensing through the AMPK and mTOR signaling pathways. May regulate phosphorylation of RPS6KB1.
Expressed in most tissues tested, including skin, lung, kidney, heart, testis and stomach.
Involvement in disease
Defects in FLCN are the cause of Birt-Hogg-Dube syndrome (BHD) [MIM:135150]. BHD is a rare autosomal dominant genodermatosis characterized by hair follicle hamartomas (fibrofolliculomas), kidney tumors, and spontaneous pneumothorax. Fibrofolliculomas are part of the triad of BHD skin lesions that also includes trichodiscomas and acrochordons. Onset of this dermatologic condition is invariably in adulthood. BHD is associated with a variety of histologic types of renal tumors, including chromophobe renal cell carcinoma (RCC), benign renal oncocytoma, clear-cell RCC and papillary type I RCC. Multiple lipomas, angiolipomas, and parathyroid adenomas are also seen in patients affected with this disease. The majority of mutations are predicted to prematurely terminate the protein. Defects in FLCN are in some cases a cause of primary spontaneous pneumothorax (PSP) [MIM:173600]. PSP is a condition in which air is present in the pleural space in the absence of a precipitating event, such as trauma or lung disease. This results in secondary collapse of the lung, either partially or completely, and some degree of hypoxia. PSP is relatively common, with an incidence between 7.4-18/100'000 for men and 1.2-6/100'000 for women and a dose-dependent, increased risk among smokers. Most cases are sporadic, typically occurring in tall, thin men aged 10-30 years and generally while at rest. Familial PSP is rarer and usually is inherited as an autosomal dominant condition with reduced penetrance, although X-linked recessive and autosomal recessive inheritance have also been suggested. Note=Defects in FLCN may be involved in renal cell carcinoma.
Belongs to the folliculin family.
Expressed in fetal lung, kidney, liver, and brain.
Phosphorylated. Several different phosphorylated forms exist.
Cytoplasm. Nucleus. Mainly localized in the nucleus. Co-localizes with FNIP1 and FNIP2 in the cytoplasm.